psych 241

Which one would we choose, hands down, whenever possible?

Complete design

Please list and describe the three main types of research designs.

Cross-sectional design = One or more samples are drawn from the population(s) at one time. CSD's allow researchers to describe the characteristics of a population or the differences between two or more populations, and correlational findings from cross-sectional designs allow researchers to make predictions Successive independent samples design = Different samples of respondents from the population complete the survey over a period of time. This design allows researchers to study changes in a population over time. The SISD does not allow researchers to infer how individual respondents have changed over time. A problem with the SISD occurs when the samples drawn from the population are not comparable- that is, not equally representative of the population Longitudinal design = The same respondents are surveyed over time in order to examine changes in individual respondents. B/c of the correlational nature of survey data, it is difficult to identify the causes of individuals' changes over time. As people drop out of the study over time (attrition), the final sample may no longer be comparable to the original sample or represent the population

What is the main role of data analysis and statistical tests in an experiment?

Data analysis and statistical tests play a critical role in researchers' ability to make the claim than an independent variable has had an effect on behavior

What are our options for summarizing the data, and when might you want to use all three?

Data can be effectively summarized numerically, pictorially, or verbally; good descriptions of data frequently use all three modes.

What do we mean by debriefing and what are some of the things researchers try to achieve with this step?

Debriefing informs participants about the nature of the research and their role in the study and educates them about the research process. The overriding goal of debriefing is to have individual feel good about their participation. Researchers are ethically obligated to seek ways to benefit participants even after the research is completed. One of the best ways to accomplish this goal is by providing participants with a thorough debriefing. Debriefing benefits both participants and researchers. Debriefing allows individuals to learn how participants viewed the procedures, allows potential insights into the nature of the research findings, and provides ideas for future research.

What do we mean by deception in psych research and how does this lead to an ethical dilemma?

Deception in psychological research occurs when researchers withhold information or intentionally misinform participants about the research. By its nature, deception violates the ethical principle of informed consent and thus leads to a great ethical dilemma. Deceiving individuals in order to get them to participate in the research is ALWAYS unethical.

Please list and describe the four main goals of the scientific method.

Description: The procedures researchers use to define, classify, catalogue, or categorize events and their relationships. Psychologists seek to describe events and relationships between variables; most often, researchers use the nomothetic approach (discovery off general scientific laws) and quantitative analysis (studies in which the findings are described using statistical summary and analysis) Prediction: When researchers identify correlations among variables they are able to predict mental processes and behavior ; correlations relationships allow psychologists to predict behavior or events, but do not allow psychologists to infer what causes these relationships. A correlation exists when two different measures of the same people, events or things vary together. Explanation: Researchers understand a phenomenon when they can identify the cause(s) of a phenomenon when 3 conditions for casual inference are met; covariation, time-order relationship, and elimination of plausible alternative causes. The experimental method, in which researchers manipulate IV's codetermine their effect on DV's, establishes time order and allows a clear determination of covariation. Plausible alternative causes for a relationship are eliminated if there are no confounding in a study. Researchers seek to generalize a study's findings to describe different populations, settings, and conditions Application: Psychologist apply their knowledge and research methods to change people's lives for the better. Psychologists conduct basic research to gain knowledge about behavior and mental processes to test theories

What do we mean by differential transfer and how can this be a problem, even for a well- balanced design?

Differential transfer occurs when the effects of one condition persist and influence performance in subsequent conditions. This can be a problem because differential transfer threatens internal validity due to the fact that it becomes impossible to determine if there are true differences between conditions.

What are the goals of the two main types of direct observational methods?

Direct observational methods can be classified as "observation without intervention" or "observation with intervention". The goals of observation without intervention are to describe behavior as it normally occurs and to examine relationships among variables Naturalistic observation helps to establish the external validity of laboratory findings. Observation with intervention has the goal or using either "undisguised" or "disguised" participant observation to allow researchers to observe behaviors and situations that are not usually open to scientific observation, structured observation to record behaviors that may be difficult to observe using naturalistic observation, and field experiment to manipulate or more independent variables in a natural setting to determine the effect on behavior

independent groups design

Each separate group of subjects in the experiment represents a different condition as defined by the level of the independent variable.

What does the effect size measure tell us?

Effect size indicates the strength of the relationship between the independent and dependent variables. Effect size also tells us how large an effect the independent variable had on the dependent variable.

How do ethical issues relate to the reporting of psychological research?

Ethical issues relate to the reporting of psychological research because researchers are expected to report their findings in a way that recognizes the work of others via proper citations and references. These ethical standards for reporting the results of a scientific investigation are put in place to ensure that the credit is given to those who have made significant contributions to the research project and that the study does not plagiarize the work of others.

How do we identify an interaction in the descriptive analyses? How is this confirmed using inferential statistics?

Evidence for interaction effects can be identified using descriptive statistics presented in graphs (i.e. nonparallel lines) or tables (subtraction method). The presence of an interaction effect is confirmed using inferential statistics in the case of graphs in which nonparallel lines in the graph suggest an interaction effect, while parallel lines suggest no interaction effect. In the case of tables, the subtraction method is used as the differences between the means in each row (or column) of the table are compared. If the differences are different, an interaction effect is likely.

correlation

Exists when two different measures of the same people, events, or things vary together; the presence of a correlation makes it possible to predict values on one variable by knowing the values on the second variable.

experimenter effects

Experimenters' expectations that may lead them to treat subjects differently in different groups or to record data in a biased manner.

What do we mean by external validity and how can we increase this validity in single case designs?

External validity is the ability of a certain study to be generalized/applied to the rest of the population, not just the individual or small group of people being studied. The problem of low external validity with single-case experiments can be reduced by testing small groups of individuals

What are the four main methods for obtaining survey data?

Four methods for obtaining survey data are mail surveys, personal interviews, telephone interviews, and internet surveys.

Why are ethical issues so important in research in general and psych research in particular?

Good science requires good scientists. Scientists'' professional competence and integrity are essential for ensuring hgh quality-science. Individual scientists and the community of scientists share responsibility for maintaining the integrity of the scientific process. Each individual scientist has an ethical responsibility to seek knowledge and to strive to improve the quality of life. Ethical issues are so important to psych research in particular because psychological researcher must treat both human and animals with respect. Psychologists also have the duty to respect the rights and dignity of research participants.

Please describe the three contexts discussed in the readings.

Historical context: An empirical approach, which relies on direct observation and experimentation for answering questions, was critical for developing the science of psychology. The computer evolution has been a key factor in the shift from behaviorism to cognitive psychology as the dominant theme in psychological inquiry. Social-Cultural context: The social and cultural context influences researchers' choice of topics, society's acceptance of findings, and the locations in which research takes place. Ethnocentric bias occurs when peoples' views of another culture are biased by the framework or lens of their own culture. Moral context: The moral context of research demands that researchers maintain the highest standards of ethical behavior. The APA's code of ethics guides research and helps researchers to evaluate ethical dilemmas such as the risks and benefits associated with deception and the use of animals in research.

What do we mean by idiographic research and how does it relate to nomothetic research?

Idiographic research (the study of individuals to identify what is unique) compliments nomothetic research (the study of groups to identify what is typical).

What additional steps should we take if the interaction effect is not statistically significant?

If an omnibus analysis of variance indicates the interaction between independent variables is not statistically significant, the next step is to determine whether the main effects of the variables are statistically significant. The source of a statistically significant main effect can be specified more precisely by performing comparisons that compare the two means two at a time and by constructing confidence intervals.

What additional steps do we need to take when we find a statistically significant interaction effect?

If the omnibus analysis of variance reveals a statistically significant interaction effect, the source of the interaction effect is identified using simple main effects analyses and comparisons of two means. The source of a statistically significant main effect can be specified more precisely by performing comparisons that compare the two means two at a time and by constructing confidence intervals.

How are inferential statistics used to test the three questions in factorial designs?

In a complex design with two independent variables, inferential statistics are used to test three effects; the main effects for each independent variable and the interaction effect between the two independent variables. Descriptive statistics are needed to interpret the results of inferential statistics. How researchers interpret the results of a complex design differs depending on whether a statistically significant interaction effect is present or absent in the data.

How does a non-equivalent control group help with that quest?

In a time series with nonequivalent control group design, researchers make a series of observations before and after treatment for both a treatment group and a comparable comparison group.

What do you think the take home Methods message is from the Langer and Rodin study?

In addition to practical considerations, the development of psychological theories plays a role when researchers test predictions about the treatment based on a theory about a behavior. When you next read or hear about research showing the beneficial effect of a treatment, look carefully to see if a treatment involved multiple components, and consider what additional research could be conducted to reveal the specific components needed to produce the positive treatment effect.

What do we mean by a multiple-baseline design, and how do we know if a treatment was effective with this design?

In multiple-baseline designs, a treatment effect is shown when behaviors in more than one baseline change only following the introduction of a treatment. Multiple baselines may be observed across individuals, behaviors, or situations. We know if a treatment was effective when we visually inspect the behavioral records which show evidence for the effectiveness of the treatment.

What are the main differences between quantitative data analysis and qualitative data analysis?

In qualitative data analysis, data reduction is an important step in the analysis of narrative and archival records. In qualitative data analysis, researchers code behaviors according to specific criteria by categorizing behaviors. Content analysis is used o examine narrative and archival records and includes the steps of identifying a relevant source, sampling sections from the source, and coding units of analysis. In quantitative data analysis, data is summarized using descriptive statistics such as frequency counts, means, and standard deviations. Quantitative data analysis also uses interobserver reliability, which refers to the extent to which independent observers agree in their observations

What do we mean by baseline observations and why are they important in single-case experiments?

In single case experiments, baseline observations are first recorded to describe what an individual's behavior is like (and predicted to be like in the future) without treatment.

What do we mean by an ABAB design and how might this lead to an ethical dilemma for researchers?

In the ABAB design, baseline (A) and treatment (B) stages are alternated to determine the effect of treatment on behavior. Researchers conclude that treatment causes behavior change when behavior changes systematically with the introduction and withdrawal of treatment. The ethical dilemma for researchers is whether or not it is ethical to remove what appears to be a beneficial treatment to determine if the treatment actually caused the improvement

F-test

In the analysis of variance, or ANOVA, the ratio of between-group variation and within-group or error variation.

What is the main difference between complete and incomplete counterbalancing?

In the complete design, practice effects are balanced for each participant by administering the conditions to each participant several times, using different orders each time. Each participant can thus be considered a "complete" experiment. In the incomplete design, each condition is administered to each participant only once.

What goals should be accomplished with each of these steps?

In the first step, means and standard deviations are computed with the goal of describing individual's performance in each condition. In the second step, summary statistics are used to represent one person's performance when that performance is "average" across trials or tests.

What do we mean by a non-equivalent control group and what are the main advantages of having one?

In the nonequivalent control group design, a treatment group and a comparison group are compared using pretest and posttest measures. If two groups are similar in their pretest scores prior to treatment but differ in their posttest scores following treatment, researchers can more confidently make a claim about the effect of treatment. Threats to internal validity due to history, maturation, testing, instrumentation, and regression can be controlled in a nonequivalent control group design

confirming what the data reveal

In the third stage of data analysis the researcher determines what the data tell us about behavior. Statistical techniques and the NHST are used to provide evidence that the results are not simply due to chance

getting to know the data

In this first stage of data analysis the researcher inspects the data for errors and outliers and generally becomes familiar with the general features of the data.

summarizing the data

In this second stage of data analysis the researcher uses descriptive statistics and graphical displays to summarize the information in a data set. Trends and patterns in the data set are described.

What are the three main characteristics of a true experimental design, and how can control be exerted here?

In true experiments, researchers manipulate an independent variable with treatment and comparison conditions and exercise a high degree of control (especially though random assignment to conditions). The three main characteristics of a true experimental design are 1) In a true experiment some type of intervention or treatment is implemented; 2) true experiments are marked by the high degree of control that an experimenter has over the arrangement of experimental conditions, assignment of participants, systematic manipulation of independent variables, and choice of dependent variables; 3) In true experiments, the experimenter establishes a proper comparison to evaluate the effectiveness of the treatment

confidence interval

Indicates the range of values which we can expect to contain a population value with a specified degree of confidence (e.g., 95%).

How are individual differences variables used to form natural groups?

Individual differences variables (or subject variables) are selected rather than manipulated to form natural groups designs

What do we mean by informed consent, and what are researchers obligated to do before starting most studies?

Informed consent is a person's explicitly expressed willingness to participate in a research project based on a clear understanding of the nature of the research, of the consequences for not participating, and of all factors that might be expected to influence that person's willingness to participate. is a social contract between researchers and participants. Individuals must be able to withdraw their consent at any time without penalties, and they must not be pressured to participate in research. Researchers are ethically obligated to describe the research procedures clearly, identify any aspects of the study that might influence individuals' willingness to participate, and answer any questions participants have about the research.

What are the two committees in charge of evaluating proposals and what type of research does each focus on?

Institutional Review Boards (IRBs) review psychological research to protect the rights and welfare of human participants Institutional Animal Care and Use Committees (IACUCs) review research conducted with animals to ensure that animals are treated humanely.

deception

Intentionally withholding information from a participant about significant aspects of a research project or presenting misinformation about the research to participants

How does variability influence our interpretation of the effect of a treatment?

Interpreting the effect of a treatment can be difficult if the baseline stage shows excessive variability or increasing or decreasing trends in behavior.

What do we mean by an intervening variable and why are they important in Psychological research?

Intervening variables are concepts used in theories to explain how and more importantly, why independent and decent variables are related. They play an important role when researchers use theories to explain their findings. They allow researchers to identify relationships among seemingly dissimilar variables

What does Cohen's d measure for us, really? Why is it considered a descriptive analysis?

It is a ratio that measures the difference between the means for the levels of the independent variable divided by the within-group standard deviation. In other words, it measures the effect of the independent variable on the mean. It is considered a descriptive analysis because as an effect size, Cohen's d is typically used to represent the magnitude of differences between two (or more) groups on a given variable, with larger values representing a greater differentiation between the two groups on that variable.

Please list and describe the three measures of central tendency that are available to us?

Mean= Most commonly reported measure of central tendency and is determined by dividing the sum of the scores by the number of scores contributing to that sum Median= Middle point in the frequency distribution; best measure of central tendency when the distribution includes extreme scores b/c it is less influenced by extreme scores than the mean is Mode= The score in the frequency distribution that occurs most often

unobtrusive methods

Measures of behavior that eliminate the problem of reactivity because observations are made in such a way that the presence of the observer is not detected by those being observed.

measures of central tendency

Measures such as the mean, median, and mode that identify a score that the data tend to center around.

measures of dispersion (variability)

Measures such as the range, standard deviation, and variance that describe the degree of dispersion of numbers in a distribution.

What do we mean by minimal risk, and at risk?

Minimal risk is when a study's procedures or activities are similar to those experienced by participants in their everyday life.

Why should we be especially skeptical about research findings we encounter in the popular media?

Not all science reported in the media is "good science." We must question what we read and hear. Media reports summarizing original research reports may omit critical aspects of the method, results, or interpretation of the research.

What does null hypothesis testing tell us about the mean difference between two groups?

Null hypothesis testing is used to determine whether mean differences among groups in an experiment are greater than the differences that are expected simply because of error variation.

What are we trying to determine with the null hypothesis significance tests? Which inferential tests would you use to compare two independent means and two paired means?

Null hypothesis testing is used to determine whether mean differences among groups in an experiment are greater than the differences that are expected simply because of error variation. The appropriate inferential test when comparing two means obtained from different groups of subjects is a t-test for independent groups. A measure of effect size should always be reported when NHST is used. The appropriate inferential test when comparing two means obtained from the same subjects (or matched groups) is a repeated measures (within-subjects) t-test.

participant observation

Observation of behavior by someone who also has an active and significant role in the situation or context in which behavior is recorded.

naturalistic observation

Observation of behavior in a more or less natural setting without any attempt by the observer to intervene.

confounding

Occurs when the independent variable of interest systematically co-varies with a second, unintended independent variable.

contamination

Occurs when there is communication of information about the experiment between groups of participants. This can lead to intergroup rivalry or diffusion of treatment between the groups.

measurement scale

One of four levels of physical and psychological measurement: nominal (categorizing), ordinal (ranking), interval (specifying distance between stimuli), and ratio (having an absolute zero point).

How do these order effects relate to the internal validity of these designs?

One potential threat to internal validity arises because participants may change over time. The repeated testing of participants in the repeated measures designs gives them practice with the experimental task. As a result of this practice, participants may get better and better at doing th task because they learn more about the task, or they may get worse at the task because of factors such as fatigue or boredom. Thus, these order effects negatively affect internal validity.

matched groups design

One type of independent groups design in which the researcher forms comparable groups by matching subjects using a matching variable and then randomly assigns the members of these matched sets of subjects to the conditions of the experiment.

How are many plausible alternatives associated with individual differences variables dealt with/eliminated in repeated measures designs?

Participants in a repeated measures design will vary within themselves less over the time of an experiment than participants in a random groups design will vary from other participants. In other words, there is more variation between people than there is within people. Thus, error variation will be less in repeated measures design.

What do we mean by practice effects, and what must we do to minimize potential order effects in repeated measures designs?

Participants' performance in repeated measures designs may change across conditions simply because of repeated testing (not because of the independent variable); these changes are called practice effects. In order to minimize potential order effects, . the order of administering the conditions is varied across participants rather than for each participant, as the case in both the complete and incomplete design

threats to internal validity

Possible causes of a phenomenon that must be controlled so a clear cause-effect inference can be made.

threats to internal validity

Potential causes of a phenomenon that must be controlled so a clear cause-effect inference can be made.

practice effects

Potential changes that participants undergo with repeated testing. Practice effects can the summation of both positive (e.g., familiarity with a task) and negative (e.g., boredom) factors associated with repeated measurement.

What step needs to be taken before any research study can be conducted?

Prior to conducting any study, the proposed research must be reviewed to determine if it meets ethical standards. Nearly every college and university require that all research conducted at the institution be review prior to data collection by an independent committee. Any individual who wants to do research must inquire of proper authorities, prior to starting research, about the appropriate procedure for institutional review.

What do we mean privacy and in what situations should individuals have an expectation of privacy?

Privacy refers to the rights of individuals to decide how information about them is to be communicated to others. Individuals should have and expectation of privacy when potentially sensitive information about them has been collected without their knowledge.

field experiment

Procedure in which one or more independent variables is manipulated by an observer in a natural setting to determine the effect on behavior.

What are the four main differences between true and quasi-experimental designs?

Quasi-experiments provide an important alternative when true experiments are not possible. Quasi-experiments lack the degree of control found in true experiments. Quasi-experiments lack random assignment. Researchers must seek additional evidence to eliminate threats to internal validity when they do quasi-experiments rather than true experiments.

Please list and describe the four measures of variability that we are often interested in.

Range= Crudest measure of dispersion (the counterpart of the mode); represented by the lowest and highest scores in the distribution Standard deviation= The most commonly used measure of dispersion (the counterpart of the mean); tells you approximately how far on average a score is from the mean; Equal to the square root of the average squared deviations of scores in the distribution about the mean Standard error= the standard deviation of the theoretical sampling distribution of means and is a measure of how well we have estimated the population mean Effect size= Important because they provide information about the strength of the relationship between the independent variable and the dependent variable that is independent of sample size; An important effect size measure when comparing two means is Cohen's d

What do mean by reactivity and why might this be a problem for survey research?

Reactivity is a phenomenon that occurs when individuals alter their performance or behavior due to the awareness that they are being observed. The change may be positive or negative, and depends on the situation. In survey research, the term reactivity applies when the individual's response is influenced by some part of the survey instrument (e.g. an item on a questionnaire); the interviewer; the survey organization sponsor conducting the study, or both; or the environment where the survey is taking place. Reactivity can invalidate survey research because it decreases the validity of the measurements.

sensitivity

Refers to the likelihood in an experiment that the effect of an independent variable will be detected when that variable does, indeed, have an effect; sensitivity is increased to the extent that error variation is reduced (e.g., by holding conditions constant rather than balancing them).

What do we mean by the reliability and validity of a measurement?

Reliability refers to the consistency of measurement and is frequently assessed using the test-reliability method. Reliability is increased by including many similar items of a measure, and by testing a diverse sample of individuals, and by using uniform testing procedures. Validity refers to the truthfulness of a measure: Does it measure what it intends to measure? Construct validity represents the extent to which a measure assesses the theoretical construct it is designed to assess; construct validity is determined by assessing convergent validity and discriminant validity

How are repeated measures designs and longitudinal designs related to each other?

Repeated measures are collected in a longitudinal study and they both use repeated observation

Why do repeated measures designs have more statistical power than independent groups designs?

Repeated measures designs are likely to be more sensitive and to have more power than independent groups designs because estimates of error variation are likely to be smaller in repeated measures designs.

replication

Repeating the exact procedures used in an experiment to determine whether the same results are obtained.

repeated measures design

Research designs in which each subject participates in all conditions of the experiment (i.e., the measurement is repeated on the same subject).

applied research

Research that seeks knowledge that will improve a situation for individuals or society.

basic research

Research that seeks knowledge to increase understanding of behavior and mental processes, and to test theories.

Why do researchers (in general) conduct experiments?

Researchers conduct experiments to test hypotheses about the causes of behavior. Experiments allow researchers to decide whether a treatment or program effectively changes behavior

How do we typically analyze data and what does this mean researchers need to do this correctly?

Researchers typical use computers to carry out the statistically analysis of data. In order to carry out statistically analysis using computer software, researchers must have good knowledge of research design and statistics

How do we determine risk levels, and what are the three main potential risks in psychological research?

Risks must be evaluated in terms of potential participants' everyday activities, their physical and mental health, and capabilities. The three main potential risks in psychological research include the risk of physical injury, social injury, and mental or emotional stress

What are the main features of an experiment and what are scientists trying to accomplish by conducting them?

Scientists gain the greatest control when they conduct an experiment. In an experiment, scientists manipulate one or more factors and observe the effects of this manipulation on behavior. The factors that the researcher controls or manipulates in order to determine their effect on behavior are called the independent variables. The independent variables have two levels. The condition in which the treatment is present is called the experimental condition; the condition in which the treatment is absent is called the control condition. The measures of behavior that are used to assess the effect (if any) of the independent variables are called dependent variables. Scientists seek to determine whether any differences in behavior (the dependent variable) are caused by the different conditions of the independent variable.

selection

Selection is a threat to internal validity when, from the outset of a study, differences exist between the kinds of individuals in one group and those in another group in the experiment. Selection is a BIG threat to internal validity when we select natural groups to form an independent groups/between-subjects variable.

What do we mean by experimental sensitivity and statistical power, and what can we do to influence the power of an experiment?

Sensitivity refers to the likelihood that an experiment will detect the effect of an independent variable, when, in fact, the independent variable truly has an effect. Power refers to the likelihood that a statistical test will allow researchers to reject correctly the null hypothesis of no group differences. The power of statistical tests is influenced by the level of statistical significance, the size of the treatment effect, and the sample size (the primary way to increase power is to increase sample size).

What do we mean by external validity and how do we evaluate that in quasi-experimental research?

Similar to internal validity, the external validity of research findings must be critically examined. External validity is the validity of applying the conclusions of a scientific study outside the context of that study. In other words, it is the extent to which the results of a study can be generalized to and across other situations, people, stimuli, and times. The best evidence for the external validity of research findings is replication with different populations, settings, and times.

What are some of the main advantages of the case study method?

Some advantages are case studies provide new ideas and hypotheses, opportunities to develop new clinical techniques, and a chance to study rare phenomena. Scientific theories can be challenged when the behavior of a single case contradicts theoretical principles or claims, and theories can receive tentative support using evidence from case studies.

What are some important characteristics of the scientific method?

Some important characteristics of the scientific method are an empirical approach and a skeptical attitude towards explanations of behavior and mental processes.

What are some of the main disadvantages of the case study method?

Some of the main disadvantages are that researchers are unable to make valid casual inferences using the case study method because extraneous variables are not controlled and several "treatments" may be applied simultaneously in case studies. Also, Observer bias and biases in data collection can lead to incorrect interpretations of case study outcomes. Furthermore, whether results from a case study may be generalized depends on the variability within the population from which the case was selected; some characteristics (i.e. personality) vary more across individuals than others (e.g. visual acuity).

sample

Something less than all the cases of interest; in survey research, a subset of the population actually drawn from the sampling frame. For example, we might sample the Methods class to say something about Psych majors.

archival records

Source of evidence based on records or documents relating the activities of individuals, institutions, governments, and other groups; used as an alternative to or in conjunction with other research methods.

physical traces

Source of evidence that is based on the remnants, fragments, and products of past behavior; used as an alternative to or in conjunction with other research methods.

Which one is not generally available to us?

Standard error of the mean

regression (to the mean)

Statistical regression can occur when individuals have been selected to participate in an experiment because of their "extreme" scores. Statistical regression is a threat to internal validity because individuals selected from extreme groups would be expected to have less extreme scores on a second test (the "posttest") without any treatment simply due to statistical regression.

What are surveys generally used for, and what do we mean by the scope of a survey?

Surveys are used to assess people's thoughts, opinions, and feelings. They can be specific and limited in scope (comparing amount of people in U.S. who are in love vs. people in France who are in love over the age of 65) or more global in their goals (measuring global happiness).

observer bias

Systematic errors in observation often resulting from the observer's expectancies regarding the outcome of a study (i.e., expectancy effects).

What do we mean by observer bias, and what steps should be taken to minimize this bias?

Systematic errors in observation often resulting from the observer's expectancies regarding the outcome of a study (i.e., expectancy effects). We can minimize this bias by first recognizing that it may be present. Observer bias may be reduced by keeping observers unaware ("blind") of the goals and hypotheses of the study

testing

Taking a test generally has an effect on subsequent testing. Testing can threaten internal validity if the effect of a treatment cannot be separated from the effect of testing.

validity

The "truthfulness" of a measure; a valid measure is one that measures what it claims to measure.

What do you need to have to be able to generalize from a sample to the population?

The ability to generalize from a sample to the population depends critically on the representativeness of the sample. A sample is representative of the population to the extent that it exhibits the same distribution of characteristics as the population.

ANOVA

The analysis of variance, or ANOVA, is the most commonly used inferential test for examining a null hypothesis when comparing more than two means in a single-factor study, or in studies with more than one factor (i.e., independent variable). The ANOVA test is based on analyzing different sources of variation in an experiment.

median

The arithmetic mean, or average, is determined by dividing the sum of the scores by the number of scores contributing to that sum. The mean is the most commonly used measure of central tendency.

Why do we go to such lengths to balance things in our experiments?

The control technique of balancing is required because these factors often cannot be held constant. The goal of random assignment is to establish equivalent groups of participants by balancing, or averaging, individual differences across the conditions. When balancing is used, researchers can logically rule out the alternative explanation that any differences we obtain between the groups on the dependent variable are due to characteristics of the participants Block randomization is important because it produces groups of equal size. This is important because the number of observations in each group affects the reliability of the descriptive statistics for each group, and it is desirable to have the reliability of these measures comparable across groups. Second, block randomization controls for time related variables. Because experiments often take substantial amount of time to complete, some participants can be affected by events that occur during the time the experiment is conducted. Block randomization also works to balance other time-related variables, such as changes in experimenters or even changes in the populations from which subjects are drawn

internal validity

The degree to which differences in performance can be attributed unambiguously to an effect of an independent variable, as opposed to an effect of some other (uncontrolled) variable; an internally valid study is free of confounds or plausible alternatives.

interobserver reliability

The degree to which two independent observers are in agreement about their observations. Similar to the correlation between the two sets of observations.

range

The difference between the highest and lowest numbers in a distribution.

simple main effect

The effect of one independent variable at one level of a second independent variable in a complex design.

baseline stage

The first stage of a single-case experiment in which a record is made of the individual's behavior prior to any intervention.

What is the first step in null hypothesis testing and how is probability theory used here?

The first step in null hypothesis testing is to assume that the groups do not differ—that is, that the independent variable did not have an effect (the null hypothesis). Probability theory is used to estimate the likelihood of the experiment's observed outcome, assuming that the null hypothesis is true. A statistically significant outcome is one that has a small likelihood of occurring if the null hypothesis were true

What are the two main steps involved in analyzing data from repeated measures designs?

The first step is to summarize participants' performance in each condition of the experiment (compute a summary score [e.g. mean, median] for each participant). The second step is to summarize the results across participants, using appropriate descriptive statistics.

casual interference

The identification of the cause or causes of a phenomenon, by establishing 1) co-variation of cause and effect, 2) a time-order relationship with cause preceding effect, and 3) the elimination of plausible alternative causes.

reactivity

The influence that an observer has on the behavior under observation; behavior influenced by an observer may not be representative of behavior that occurs when an observer is not present.

What do we mean by reactivity, and what methods might be used to minimize reactivity?

The influence that an observer has on the behavior under observation; behavior influenced by an observer may not be representative of behavior that occurs when an observer is not present. We can minimize this reactivity by concealing the observer's presence, adaptation (habituation, desensitization), and indirect observation (physical traces, archival records). Researchers must consider ethical issues when attempting to control reactivity.

coding

The initial step in data reduction, especially with narrative records, in which units of behavior or particular events are identified and classified according to specific criteria.

What is the logic of the Analysis of Variance (ANOVA) and what test do we use to determine whether our independent variable had a statistically significant effect on a dependent variable?

The logic of analysis of variance is based on identifying sources of error variation and systematic variation in the data. Analysis of variance (ANOVA) is an inferential statistics test used to determine whether an independent variable has a statistically significant effect on a dependent variable.

What are two important characteristics of an independent random groups design?

The logic of the design is straightforward. The groups are formed so as to be similar on all important characteristics at the start of the experiment. Next, in the experiment itself, the groups are treated the same except for the level of the independent variable. Thus, any difference between the groups on the dependent variable must be caused by the independent variable.

What do you see as the main advantages of repeated measures designs?

The main advantages of repeated measures designs are the ability to conduct an experiment when few participants are available, conduct the experiment more efficiently, increase the sensitivity of the experiment, and study changes in participants' behavior over time.

What is the main difference between a case study and a single case experimental design?

The main difference between a case study and. A single case experimental design is that in a case study, you do not have a high degree of control over the test subjects, but in a single case experimental design, experimental control is demonstrated by arranging experimental conditions such that the individual's behavior changes systematically with the manipulation of an independent variable.

What are the main steps involved in creating a questionnaire?

The main steps are: 1) Decide what information should be sought 2) Decide how to administer the questionnaire 3) Prepare a draft of questionnaire 4) Reexamine and revise the questionnaire 5) Pretest the questionnaire 6) Edit the questionnaire and specify the procedures to be followed in its administration

What are dependent variables and what can they tell us in experiments?

The measures of behavior that are used to assess the effect (if any) of the independent variables are called dependent variables. A dependent variable is the variable being tested and measured in a scientific experiment.The dependent variable is 'dependent' on the independent variable. As the experimenter changes the independent variable, the effect on the dependent variable is observed and recorded.

block randomization

The most common technique for carrying out random assignment in the random groups design; each block includes a random order of the conditions, and there are as many blocks as there are subjects in each condition of the experiment.

random assignment

The most common technique for forming groups as part of an independent groups design; the goal is to establish equivalent groups by balancing individual differences.

random groups design

The most common type of independent groups design in which subjects are randomly assigned to each group such that groups are considered equal at the start of the experiment.

standard deviation

The most commonly used measure of dispersion that indicates approximately how far on the average scores differ from the mean.

history

The occurrence of an event other than the treatment that can threaten internal validity if it produces changes in the research participants' behavior.

What do they mean by the pre-experimental design and why does it have so little internal validity?

The one-group pretest-posttest design is called a pre-experimental design or bad experiment because it has so little internal validity. Any obtained difference between the pretest and posttest scores could be due to the treatment or to any of the several threats to internal validity, including history, maturation, testing, and instrumentation threats (as well as experimenter expectancy effects and novelty effects)

main effect

The overall effect of an independent variable in a complex design

plagiarism

The presentation of another's ideas or work without clearly identifying the source.

How is the ANOVA different for Repeated Measures designs and how/why does this impact the power of the statistical tests?

The primary way that analysis of variance for repeated measures differs is the estimation of error variation, or residual variation; residual variation is the variation that remains when systematic variation due to the independent variable and subjects is removed from the estimate of total variation. The ability to eliminate systematic variation due to participants makes these designs have more power than independent groups designs since the error estimate is smaller, as this leads to a larger ratio.

power

The probability in a statistical test that a false null hypothesis will be rejected; power is related to the level of significance selected, the size of the treatment effect, and the sample size.

Type II error

The probability of failing to reject the null hypothesis when it is false.

Type I error

The probability of rejecting the null hypothesis when it is true, equal to the level of significance, or alpha.

level of significance

The probability when testing the null hypothesis that is used to indicate whether an outcome is statistically significant. Level of significance, or alpha, is equal to the probability of a Type I error.

situation sampling

The random or systematic selection of situations in which observations are made with the goal of representativeness across circumstances, locations, and conditions.

privacy

The right of individuals to decide if and how information about them is communicated to others.

What do we mean by the Risk/Benefit ratio and what is it used for?

The risk/benefit ratio asks the questions "Is it worth it?" and "Are the benefits greater than the risks?" It is a subjective evaluation of the risks and benefit of a research project and is used to determine whether the research should be conducted.

Who benefits from this scientific approach, potentially?

The scientific approach can potentially benefit anyone impacted by the information gained from research, which extends far past the individual researchers. This is because the scientific method strives to provide unbiased answers to questions of interest. Ultimately, the set standards provided by the scientific approach can benefit all people by giving researchers a systematic and more comparable way to learn and advance knowledge.

What are some keys aspects of the scientific method?

The scientific method does not require a particular type of experiment, nor is it associated with a particular procedure or technique. The SM refers to the ways in which scientists ask questions an the logic and methods used to gain answers. The SM is empirical and requires systematic, controlled observation and experimentation. The SM requires youtube skeptical, unbiased, accurate, precise, and objective. By using the SM, psychologists seek to avoid the confirmation bias- our natural tendency to seek evidence that is consistent with our intuitions and ignore or deny contradictory evidence.

What do we mean by the scientific method, and what are we able to gain through this approach?

The scientific method is an abstract concept that refers to the ways in which questions are asked and the logic and methods used to gain answers. Psychologists are able to answers questions about behaviors, thoughts, and feelings through this approach. This approach requires that researchers investigate a research question in an unbiased way with a skeptical outlook. The scientific method aims to provide a more reliable way to produce new knowledge that is less subject to personal opinions or incentives. This is import because it allows researchers to compare their results to the results of different studies and then form ideas based off of this information.

mode

The score that appears most frequently in the distribution. There can be more than one mode.

time sampling

The selection of observation intervals either systematically or randomly with the goal of obtaining a representative sample of behavior.

population

The set of all the cases of interest for each specific study.

What does it mean for an experiment to have a 2 x 2 design? What happens if you start adding more levels OR other variables?

The simplest complex design is a 2 x 2 design--two independent variables, each with two levels. More powerful and efficient complex designs can be created by including more levels of an independent variable or by including more independent variables in the design.

standard error of the mean

The standard deviation of the sampling distribution of means.

Which of the three criteria for internal validity do these refer to?

The threats to internal validity refer to the "elimination of plausible alternative cases"

What threats still remain plausible in the non-equivalent control group designs?

The threats to internal validity that must be considered when using the nonequivalent control group design include additive effects with selection, differential regression, observer bias, contamination, and novelty effects.

Which threats can we minimize and which ones remain plausible, even in true experimental designs?

The threats we can minimize are threats to external validity. Threats to internal validity remain plausible even in true experimental designs. These threats include contamination, experimenter expectancy effects, and novelty effects.

What are the three Ss and how do they relate to the decision regarding what information is private?

The three Ss are the sensitivity of the information, the setting, and the method of dissemination of the information. Some kinds of information are more sensitive than others. The setting plays a role in deciding whether behavior is public or private. When information is disseminated in terms of group averages or proportions, it is unlikely to reveal much about specific individuals. In other situations, code systems can be used to protect participants' confidentiality.

What are the three main methods of observation with intervention? Why is it important if the participant observer is disguised or undisguised?

The three main methods of observation with intervention are participant observation, structured observation, and the filed experiment Participant observation= using either "undisguised" or "disguised" participant observation to allow researchers to observe behaviors and situations that are not usually open to scientific observation. Structured observation= record behaviors that may be difficult to observe using naturalistic observation Field experiment= researchers manipulation or more independent variables in a natural setting to determine the effect on behavior It is important if the participant observer is disguised or undisguised because if individuals change their behavior when they know they are being observed ("reactivity"), their behavior may no longer be representative of their normal behavior

What are some of the common descriptive measures that are used to summarize the results of experiments?

The two most common descriptive measures are effect size, or d, which examines the difference between two group means relative to the average variability in the experiment, and meta-analysis, which uses measures of effect size to summarize the results of many experiments investigating the same independent variable or dependent variable.

How are interaction effects used to test theories, and how do they relate to the external validity for the independent variables?

Theories frequently predict that two or more independent variables interact to influence behavior; therefore, complex designs are needed to test theories. Tests of theories can sometimes produce contradictory findings. Interaction effects can be useful in resolving these contradictions. Interaction effects relate to the external validity for the independent variables as the presence of an interaction effect identifies boundaries for the external validity of a finding by specifying the conditions in which an effect of an independent variable occurs. Additionally, when no interaction effect occurs in a complex design, the effects of each independent variable can be generalized across the levels of the other independent variable; thus, external validity of the independent variables increases.

novelty effects

Threats to internal validity of a study that occur when people's behavior changes simply because an innovation (e.g., a treatment) produces excitement, energy, and enthusiasm; a Hawthorne effect is a special case of novelty effects.

stages of data analysis

Three stages of data analysis are getting to know the data, summarizing the data, and confirming what the data reveal.

What three steps are needed for making a causal inference involving natural groups?

Three steps for making a causal inference involving a natural groups variable are to state a theory for why group differences exist, manipulate an independent variable that should demonstrate the theorized process, and test whether an interaction effect occurs between the manipulated independent variable and natural groups variable

What are the two main domains of sampling and why is sampling so important for external validity?

Time sampling refers to researchers choosing time intervals for making observations either systematically or randomly. When researchers are interested in events that happen infrequently, they rely on event sampling to sample behavior. Situation sampling involves studying behavior in different location and under different circumstances and conditions. Situation sampling enhances the external validity of findings. Within situations, subject sampling may be used to observe only some individuals in the setting. Sampling is so important for external validity because it gains important information about different populations, settings, and conditions through the process of observations. Sampling is used to enhance the external validity of observational findings.

What do you think the most important aspect of thinking like a researcher is, really?

To "think like a researcher" is to be skeptical regarding claims about the causes of behavior and mental processes, even those that are made of the basis of "published" scientific findings. I think that the most important aspect of thinking like a researcher is to set aside personal biases and preconceptions, and to have the courage to face evidence no matter where it leads.

What two approaches can we take to make a case for a causal inference?

Two approaches that we can take to measure a case for a causal interference are null hypothesis testing and confidence intervals

structured observation

Variety of observational methods using intervention in which the degree of control is often less than in field experiments; frequently used by clinical and developmental psychologists when making behavioral assessments.

What are we trying to achieve with the descriptive analyses?

We are trying to determine how large an effect the independent variable had on the dependent variable. Descriptive analyses asks the question "What happened in the experiment?"

What do they mean by getting to know the data, and what are some of the main steps we take to do this?

We begin data analysis by examining the general features of the data and edit or "clean" the data as necessary. It is important to check carefully for errors such as missing or impossible values (e.g. numbers outside the range of a given scale), as well as outliers. A stem-and-leaf-display is particularly useful for visualizing the general features of a data set and for detecting outliers.

Why can't we draw a causal conclusion even if we find significant differences between these groups?

We can't draw a causal conclusion even if we find significant differences between these groups because plausible alternative explanations for group differences exist

Why do we like to use complex/factorial designs, and what are our two options for independent variables within these designs?

We like to use complex/factorial designs because we can study the effects of two or more independent variables in one experiment. In addition, each independent variable can be studied with an independent group design or with a repeated measures design.

How do the three types of significance differ from each other?

We must recognize the fact that statistical significance is not the same as scientific significance. We also must acknowledge that statistical significance is not the same as practical or clinical significance.

What do we need to keep in mind when evaluating individuals' testimonials?

We need to keep in mind the limitations of the case study method, as this can be helpful when evaluating individuals' testimonials about the effectiveness of a particular treatment

How did you use this approach in the Stroop project from lab? What value was particularly important in that case?

We used this approach in the Stroop project from lab by comparing the means from two conditions; the no label condition and the incongruent label condition.

spurious relationship

What exists when evidence falsely indicates that two or more variables are associated when they are not in reality. A correlation could be present between two variables but there is a third variable that is causing the changes in both of these variables. For example, the correlation between the sales of ice cream the number of violent crimes in some cities is considered to be a spurious relationship.

Please list and describe the three questions that can be asked in a 2 x 2 factorial design?

What is the first independent variable (random groups design)? What is the second independent variable (naturals group design)? What is the factorial Combination of two independent variables (repeated measures group design)?

What does it mean for a sample to be representative of a population? What does a representative sample allow, in regards to that population?

When a complete record of behavior cannot be obtained, researchers seek to obtain a representative sample of behavior. Typically only certain behaviors occuruing at particular times, in specific settings, and under particular conditions can be observed. In other words, behavior must be sampled. This sample s used to represent the larger population of all possible behaviors. By choosing times, settings, and conditions for their observations that are representative of a population of behaviors, researchers can generalize their findings to that population. Results can be generalized only to participants, times, settings, and conditions similar to those in the study in which observations were made. The key feature of representative samples is that they are "like" the larger population from which they are drawn.

What does it mean when an experiment has external validity?

When an experiment has external validity, the findings of an experiment can be applied to other individuals, settings, and conditions beyond the scope of the specific experiment.

The Analysis Story

When data analysis is completed, we must construct a coherent narrative that explains our findings, counters opposing interpretations, and justifies our conclusions.

How do ceiling or floor effects cause big problems for interpreting interactions?

When participants' performance reaches a maximum (ceiling) or a minimum (floor) in one or more conditions of an experiment, results for an interaction are unpredictable

interaction effect

When the effect of one independent variable differs depending on the level of a second independent variable.

What do we mean by threats to internal validity and what are some of the main examples that we should be on the look out for?

When the independent variable of interest and a different, potential independent variable are allowed to covary, a confounding is present, and thus there is a threat to internal validity. The main examples we should look out for are if groups differ on a factor other than the main independent variable, as the results of the experiment become uninterpretable. In addition, if other additional confounding factors, such as the temperature of the room in an experimentation room, is changed for each participant, the results of the experiment could also be skewed and thus a threat to internal validity is present.

statistically significant

When the probability of an obtained difference in an experiment is smaller than would be expected if error variation alone were assumed to be responsible for the difference, the difference is statistically significant.

What do we mean when we say correlation does not imply causation? What does it mean for an apparent relationship to be spurious?

When two variables are related (correlated), we can make predictions for the variables; however, we cannot, simply knowing a correlation, determine the cause of the relationship. When a relationship between two variables can be explained by a third variable, the relationship is said to be "spurious."

How do we deal with risk in research, and what needs to happen as risks become greater?

Whether "at risk" or "at minimal risk," research participants must be protected. More safeguards are needed as risks become greater. To protect participants from social risks, information they provide should be anonymous, or if that isn't possible, the confidentiality of their information should be maintained.

What three recommendations do they have for comparing two means?

1) Keep in mind the final goal of data analysis: to make a case based on our observations for a claim about behavior. In order to make the best case possible, you will want to explore various alternatives for data analysis 2) When using NHST be sure to understand its limitations and what the outcome of NHST allows you to say 3) Researchers must "break the habit" or relying soley on NHST and consider reporting confidence intervals for effect size in addition to, or even rather than, p values associate with results of inferential tests

individual differences variable

A characteristic or trait that varies consistently across individuals, such as level of depression, age, intelligence, gender. Because this variable is formed from preexisting groups (i.e., it occurs "naturally"), an individual differences variable is sometimes called a natural groups variable. Another term sometimes used synonymously with individual differences variable is Subject variable.

construct

A concept or idea used in psychological theories to explain behavior or mental processes; examples include aggression, depression, intelligence, memory, and personality.

counterbalancing

A control technique for distributing (balancing) practice effects across the conditions of a repeated measures design. How counterbalancing is accomplished depends on whether a complete or an incomplete repeated measures design is used.

experiment

A controlled research situation in which scientists manipulate one or more factors and observe the effects of this manipulation on behavior.

How are the two steps of data analysis discussed above applied to a correlational study?

A correlation exists when two different measures of the same people, events, or things vary together—that is, when scores on one variable covary with scores on another variable. Step 1: Getting to know the data = each respondent provides two scores, and both sets of scores should be checked carefully for errors such as impossible values or outliers; A stem and leaf display may be used to examine the data in each set Step 2: Summarizing the data = the major descriptive techniques for correlational data are the construction of a scatterplot and the calculation of a correlation coefficient; the magnitude or degree of correlation is seen in a scatterplot by demining how well the points correspond to a straight line; stronger correlations more clearly resemble a straight line (linear trend) of points; the magnitude of a correlation coefficient ranges from -1.0 ( a perfect negative relationship) to +1.0 (a perfect positive relationship); a correlation coefficient of 0.0 indicates no relationship Step 3: Constructing a confidence interval for a correlation = We can obtain a confidence interval estimate of the population correlation, p, just as we did for the population mean, µ

independent variable

A factor/variable for which the researcher manipulates at least two levels in order to determine its effect on behavior, if any.

Cohen's d

A frequently used measure of effect size in which the difference in means for two conditions is divided by the average variability of participants' scores (within-group standard deviation). Based on Cohen's guidelines, d values of .20, .50, and .80 represent small, medium, and large effects, respectively, of an independent variable.

How do we, as a research community, evaluate the validity of theories?

A good scientific theory is one that is able to pass the most rigorous tests. The research community evaluates the validity of a theory by first considering if it proposes a logical argument free of contradictions. Next, the hypothesis proposed by the theory is subjected to scrutiny. If the theory is successful, testing of the derived hypothesis will increase the acceptability of the hypothesis, though this may be difficult. Lastly, the scientific community examines if the theory is precise and follows the rule of parsimony by proposing the simplest explanation for the phenomena.

scatterplot

A graph showing the relationship between two continuous variables by indicating the intersection of two measures obtained from the same person, thing, or event.

How would you describe a hypothesis, and what aspects are important in creating a strong testable hypothesis?

A hypotheses is is a tentative explanation or something. Hypotheses frequently attempt to answer the questions "How?" And "Why?" At one level, a hypothesis may simply suggest how particular variables are related. One characteristic that dustingishes casual, everyday hypotheses from scientific hypotheses is testability. If a hypothesis cannot be tested, it is not useful to science. A hypothesis' constructs must be adequately defined, it must be linear, NOT circular, and the hypothesis must appeal to ideas that are recognized by science. A hypothesis is testable f the concepts to which they refer are adequately defined and measured.

control

A key component of the scientific method whereby the effects of various factors possibly responsible for a phenomenon are isolated. Three basic types of control are manipulation, holding conditions constant, and balancing across conditions.

theory

A logically organized set of propositions that serves to define events, describe relationships among events, and explain the occurrence of these events. Scientific theories guide research and organize empirical knowledge

When might you deliberately use a matched group design, and how should you assign the subjects to your experimental conditions?

A matched group design ay be used to create comparable groups when there are too few subjects available for random assignment to work effectively. Matching subjects on the dependent variable (as a pretest) is the best approach for creating matched groups, but scores on any matching variable must correlate with the dependent variable. After subjects are matched on the matching variable, they should then be randomly assigned to the conditions of the independent variable.

dependent variable

A measure of behavior used by the researcher to assess the effect (if any) of the independent variable. Many dependent variables are available in psychological research.

eta squared (η2)

A measure of the strength of association (or effect size) based on the proportion of variance accounted for by the effect of the independent variable on the dependent variable.

reliability

A measurement is reliable when it is consistent.

ceiling (and floor) effect

A measurement problem whereby the researcher cannot measure the effects of an independent variable or a possible interaction effect because performance has reached a maximum (minimum) in any condition of the experiment.

What is the multi-method approach, and what does it offer for psychological and brain sciences?

A multi-method approach, one that searches for answers using various research methodology and measures, is psychology's best hope for obtaining a complete understanding of behavior and the mind.

ethnocentric bias

A potential bias to interpret or understand the behavior of individuals in different cultures based on the views in one's own culture.

differential transfer

A potential problem in repeated measures designs when performance in one condition differs depending on the condition preceding it.

placebo control group

A procedure by which a substance that resembles a drug or other active substance but that is actually an inert, or inactive, substance is given to participants.

double-blind procedure

A procedure by which both the participant and the observer are kept unaware (blind) of what treatment is being administered.

Null Hypothesis Significance Testing (NHST)

A procedure for statistical inference used to decide whether a variable has produced an effect in a study. NHST begins with the assumption that the variable has no effect (see null hypothesis), and probability theory is used to determine the probability that the effect (e.g., a mean difference between conditions) observed in a study would occur simply by error variation ("chance"). If the likelihood of the observed effect is small (see level of significance), assuming the null hypothesis is true, we infer the variable produced a reliable effect.

single-case experiment

A procedure that focuses on behavior change in one individual by systematically contrasting conditions within that individual while continuously monitoring behavior.

operational definition

A procedure whereby a concept is defined solely in terms of the observable procedures used to produce and measure it.

debriefing

A process following a research session through which participants are informed about the rationale for the research in which they participated, about the need for any deception, and about their specific contribution to the research. Important goals of debriefing are to clear up any misconceptions and to leave participants with a positive feeling toward psychological research.

data reduction

A process in the analysis of behavioral data whereby results are meaningfully organized and statements summarizing important findings are prepared.

nonequivalent control group design

A quasi-experimental procedure in which a comparison is made between control and treatment groups that have been established on some basis other than through random assignment of participants to groups. These may be pre-existing groups selected because they are similar but are considered nonequivalent because they haven't been randomly assigned. Other differences may exist.

simple interrupted time-series design

A quasi-experimental procedure in which changes in a dependent variable are observed for some period of time both before and after a treatment is introduced.

time series with nonequivalent control group design

A quasi-experimental procedure that improves on the internal validity of a simple time-series design by including a nonequivalent control group; both treatment and comparison groups are observed for a period of time both before and after the treatment.

positive correlation

A relationship between two variables in which values for one measure increase as the values of the other measure also increase.

negative correlation

A relationship between two variables in which values for one measure increase as the values of the other measure decrease.

cross-sectional design

A research design in which one or more samples of the population are selected and information is collected from the samples at one time.

longitudinal design

A research design in which the same sample of respondents is interviewed/surveyed (or some other DV is measured) more than once.

What do we mean by a theory, and a hypothesis, and how are these two related to each other?

A research hypothesis is tentative explanation for a phenomenon; it is often stated in the form of a prediction together with an explanation for the predicted outcome. Researchers generate hypotheses in many ways, but they always review published psychological studies before beginning their research. A theory, on the other hand, is supported by evidence and functions as a unifying explanation for several already supported hypotheses. In the context of psychology, a theory takes information gained from several tested hypotheses to develop a model for some aspect of thought or behavior. This means that a hypothesis functions as a kind of building block that can provide knowledge for producing a more encompassing scientific theory.

minimal risk

A research participant is said to experience minimal risk when probability and magnitude of harm or discomfort anticipated in the research is not greater than that ordinarily encountered in daily life or during the performance of routine tests.

representativeness

A sample is representative of a population to the extent that it has the same distribution of characteristics as the population from which it was selected. Our ability to generalize from sample to population is critically dependent on representativeness. The Methods class might be representative of Psych majors (debatable) but would not be representative of all UMass students.

probability sampling

A sampling procedure in which the probability that each element of the population will be included in the sample can be specified.

nonprobability sampling

A sampling procedure in which there is no way to estimate the probability of each element's being included in the sample. A common type is convenience sampling.

questionnaire

A set of predetermined questions for all respondents that serves as the primary research instrument in survey research

ABAB design (reversal design)

A single-case experimental design in which an initial baseline stage (A) is followed by a treatment stage (B), a return to baseline (A), and then another treatment stage (B). The researcher observes whether behavior changes on introduction of the treatment, reverses when the treatment is withdrawn, and improves again when the treatment is reintroduced.

Multiple-baseline design

A single-case experimental design in which the effect of a treatment is demonstrated by showing that behaviors in more than one baseline change as a consequence of the introduction of a treatment. Multiple baselines can be established 1) for different individuals, 2) for different behaviors in the same individual, or 3) for the same individual in different situations.

risk/benefit ratio

A somewhat subjective evaluation of the risk to a research participant relative to the benefit both to the individual and to society of the results of the proposed research.

comparison of two means

A statistical technique that can be applied (usually after obtaining a significant omnibus F-test) to locate the specific source of systematic variation in an experiment by comparing means two at a time.

correlation coefficient

A statistical test indicating how well two measures vary together; absolute size ranges from 0.0 (no correlation) to 1.00 (perfect correlation). The direction of covariation is indicated by the sign of the coefficient, a plus (+) indicating that both measures covary in the same direction and a minus (−) indicating that the variables vary in opposite directions.

Can you come up with a study that would use both longitudinal AND repeated measures designs?

A study that would use both longitudinal and repeated measures design would first observe the effect of using a Juul over a year long period. Researchers would make observations about a group of 20 individuals who regularly use their e-cigarette over the course of 1 year, specifically the affect that constant Juul use (indicative of a nicotine addiction) has on their overall health. This part of the experiment would be classified as a longitudinal design. Then, researchers will introduce 6 different treatments to the same group over individuals over the course of 1 year. Thus, each individual will receive 6 different treatments for 2 months each. These treatments are designed to significantly reduce time spend using e-cigarettes, as well as permanently reduce the detrimental health effects of e-cigarette use. The treatments include: 1) Stop juuling all together (cold turkey) while exercising personal self-control 2) Admittance into a group therapy program 3) Individual therapy 4) Nicotine patch 5) Prescription of anti-nicotine drug varenicline 6) Control variable (use Juul regularly) This portion of the experiment is classified as a repeated measures design

stem-and-leaf display

A technique for visualizing both the general features of a data set and specific item information by creating leading digits as "stems" and trailing digits as "leaves."

hypothesis

A tentative explanation for a phenomenon. The hypothesis is usually based on a theory and makes a prediction that can be tested to provide evidence for or against the theory.

What do we mean by a theory, and what are three important aspects of a good scientific theory?

A theory is a proposed explanation for the causes of phenomena, and it varies in scope and level of explanation. A scientific theory is a logically organized set of propositions that defies events, describes relationships among events, and explains the occurrence of events. Successful scientific theories organize empirical knowledge, guide research by offering testable hypothesizes, and survive rigorous testing.

subject attrition

A threat to internal validity occurs when participants are lost systematically from the study, for example, when participants drop out of the research project. The loss of participants can change the nature of a group from that established prior to the introduction of the treatment—for example, by destroying the equivalence of groups that had been established through random assignment.

response rate bias

A threat to the representativeness of a sample that occurs when some participants selected to respond to a survey systematically fail to complete the survey (e.g., due to failure to complete a lengthy questionnaire or to comply with a request to participate in a phone survey).

selection bias

A threat to the representativeness of a sample that occurs when the procedures used to select a sample result in the over- or underrepresentation of a significant segment of the population.

linear trend

A trend in the data that is appropriately summarized by a straight line.

interviewer bias

A type of bias that occurs when the interviewer influences the data collection. Examples include adjusting the wording of a question to fit the respondent or recording only selected portions of the their answers.

natural groups design

A type of independent groups design in which the conditions represent the selected levels of a naturally occurring independent variable, for example, the variables age or gender.

simple random sampling (random selection)

A type of probability sampling in which each possible sample of a specified size in the population has an equal chance of being selected.

stratified random sampling

A type of probability sampling in which the population is divided into subpopulations called strata and random samples are drawn from each of these strata.

quasi-experiments

A variety of procedures that resemble characteristics of true experiments, for example, that some type of intervention or treatment is used and a comparison is provided, but are lacking in the degree of control found in true experiments. This lack of control is often the inability to randomly assign Subs.

Why does it matter that science occurs within different contexts?

Although the concept of the scientific method may be abstract, the practice of psychological science is very much a concrete human activity that affects us on several levels (individual, family, and society). Human activities are influenced heavily by the context in which they occur, and scientific activity is no exception. We can suggest that at least three contexts play a critical role in influencing science: historical context, social-cultural context, and moral context

empirical approach

An approach to acquiring knowledge that emphasizes direct observation and experimentation as a way of answering questions.

scientific method

An approach to knowledge that emphasizes empirical rather than intuitive processes, testable hypotheses, systematic and controlled observation of operationally defined phenomena, data collection using accurate and precise instrumentation, valid and reliable measures, and objective reporting of results. Scientists tend to be critical and, most importantly, skeptical.

nomothetic approach

An approach to research that seeks to establish broad generalizations or laws that apply to large groups (populations) of individuals. The average or typical performance of a group is emphasized.

null hypothesis (H0)

An assumption used as the first step in statistical inference whereby the independent variable is said to have had no effect (or there is no difference).

estimated standard error of the mean

An estimate of the true standard error obtained by dividing the sample standard deviation by the square root of the sample size.

What three conditions need to be met for an experiment to have internal validity?

An experiment has internal validity when it fulfills the three conditions required for causal interference: covariation, time-order relationship, and elimination of plausible alternative causes

complex design

An experiment in which two or more independent variables are studied simultaneously.

single-factor independent groups design

An experiment that involves independent groups with one independent variable.

informed consent

An explicitly expressed willingness to participate in a research project based on clear understanding of the nature of the research, of the consequences of not participating, and of all factors that might be expected to influence willingness to participate.

What are indirect observational methods and why have archival records become so important in recent years?

An important advantage of indirect observational methods is that they are nonreactive. Indirect, unobtrusive observations can be obtained by examining physical traces and archival records. Archival records have become so important in recent years because they are the public and private documents describing the activities of individuals, groups, institutions, and governments, and comprise running records and records of specific, episodic events. Archival date are used to test hypotheses as part of the multimethod approach, to establish external validity of laboratory findings, and to assess the effects of natural treatments

What do the confidence intervals tell us about the population parameter of interest?

An important approach to confirming what the data are telling us is to construct confidence intervals for the population parameter, such as a mean of difference between two means

relevant independent variable

An independent variable that has been shown to influence behavior, either directly, by producing a main effect, or indirectly, by resulting in an interaction effect in combination with a second independent variable

t-test for independent groups

An inferential test for comparing two means from different groups of subjects.

repeated measures (within-subjects) t-test

An inferential test for comparing two means from the same group of subjects or from two groups of subjects "matched" on some measure related to the dependent variable.

idiographic approach

An intensive study of an individual, with an emphasis on both individual uniqueness and consistency/lawfulness.

effect size

An measure of the strength of the relationship between the independent variable and dependent variable that is independent of sample size.

meta-analysis

Analysis of results of several (often, very many) independent experiments investigating the same research area; the measure used in a meta-analysis is typically effect size

What is the difference between basic and applied research and how do these two approaches relate to each other?

Basic Research refers to the study that is aimed at expanding the existing base of scientific knowledge. Applied Research is the research that is designed to solve specific practical problems or answer certain questions. Basic and applied research are similar to each other because they both strive to find new knowledge and lead to find innovative technologies.

What is the difference between Type I and Type II errors and which type is more common in most research? Why did they set it up that way?

Because decisions about the outcome of an experiment are based on probabilities, error may occur: Type I (rejecting a true null hypothesis) or Type II (failing to reject a false null hypothesis). Type II errors are more common in research. The probability of making a Type I error can be reduced simply by making the level of significance more stringent, perhaps 0.01. This, however, increases the likelihood of making a Type II error. Type II errors are more common because of low statistical power in many psychological studies.

selective survival

Bias that results from the way physical traces and archives survive over time; when present, the bias severely limits the external validity of research findings.

selective deposit

Bias that results from the way physical traces are laid down and the way archival sources are produced, edited, or altered, as they are established; when present, the bias severely limits generality of research findings.

Why is selection of the sample so important in many types of research?

Careful selection of survey sample allows researchers to generalize findings from the sample to the population. Researchers are not interested simply in the responses of those surveyed; instead, they seek to describe the arger population from which the sample was drawn.

What are some of the main characteristics of the case study method?

Case studies, intensive descriptions and analyses of individuals, lack the degree of control found in small-n experimental designs. They are a source of hypotheses and ideas about normal and abnormal behavior. Case studies frequently make use of qualitative data. A fundamental characteristic of case studies is that they often lack a high degree of control. Case studies are interrelated and complementary to other research methods in psychology.

maturation

Change associated with the passage of time per se is called maturation. Changes participants undergo during an experiment that are due to maturation and not due to the treatment can threaten internal validity.

instrumentation

Changes over time can take place not only in the participants of an experiment, but also in the instruments used to measure the participants' performance. These changes due to instrumentation can threaten internal validity if they cannot be separated from the effect of the treatment.

multimethod approach

An approach to hypothesis testing that seeks evidence by collecting data using several different research procedures and measures of behavior. This approach is a recognition of the fact that any single study is susceptible to error in the measuring process.

correlational research

Research to identify predictive relationships among naturally occurring variables

external validity

The extent to which the results of a research study can be generalized to different populations, settings, and conditions.

theory

A logically organized set of propositions that serves to define events, describe relationships among events, and explain the occurrence of these events. Scientific theories guide research and organize empirical knowledge.

confidence interval for a population parameter

A range of values around a sample statistic (e.g., a sample mean) with specified probability (e.g., .95) that the population parameter (e.g., population mean) has been captured within that interval.

narrative record

A record intended to provide a more or less faithful reproduction of behavior as it originally occurred.

successive independent samples design

A research design in which a series of cross-sectional surveys is done and the same questions are asked of each succeeding sample of respondents.

What is the logic of experimental research?

Researchers manipulate an IV in an experiment to observe the effect on behavior, as assess by the dependent variable. Experimental control allows researchers to make the causal inference The scientific method requires systematic and controlled observations.

What are we trying to achieve with the inferential statistics?

Researchers use inferential statistics to determine whether an independent variable has a reliable effect on a dependent variable

case study

An intensive description and analysis of a single individual.

demand characteristics

Cues and other information used by participants to guide their behavior in a psychological study, often leading participants to do what they believe the observer (experimenter) expects them to do.

What do we mean by a simple interrupted time-series, and what are we looking for in these designs?

In a simple interrupted time-series design, researchers examine a series of observations both before and after a treatment. Evidence for treatment effects occurs when there are abrupt changes (discontinuities) in the time-series data at the time the treatment was implemented.

social desirability

Subtle pressures on subjects to answer as they think they should respond in accordance with what is most socially acceptable, and not in accordance with what they might actually believe.

How do we determine the number of different conditions in an experimental design?

The number of different conditions in a complex design can be determined by multiplying the number of levels for each independent variable (e.g. 2 x 2= 4)

Why do psychologists develop theories and conduct psychological research?

They develop theories and conduct physical research in order to answer questions about behavior and mental processes. These answers can impact individuals and society.

What do we mean by threats to internal validity and what are eight main types of these threats?

Threats to internal validity are confounds that serve as plausible alternative explanations for a research finding. Major classes of threats to internal validity include history, maturation, testing, instrumentation, regression, subject attraction, selection, and additive effects with selection.

What are the two main approaches to sampling and what is the main difference between them?

Two approaches to selecting a survey sample are probability sampling and nonprobability sampling. Probability sampling is the method of choice for obtaining a representative sample. In simple random sampling, each element of the population has an equal chance of being included in the sample; in stratified random sampling, the population is divided into subpopulations (strata), and random samples are drawn from the strata. Nonprobability sampling (such as convenience sampling) does not guarantee that every element in the population has an equal chance of being included in the sample. Probability sampling (Simple RS and stratified RS) does.