AP PYSCH chap. 2

Descriptive statistics

Ways of describing a set of data. Measures of central tendency are a common example. These common measures of central tendency are the mean, median and mode

Scatter plot

A graph of correlated data. Graph pairs of values The closer the points fall to a straight line, the stronger the correlation.

Normal curve

A bell-shaped curve that represents a distribution of scores that is normally distributed ( a few scores at the low end and the high end of the distribution, with most of the scores clustered around the mean)

Random assignment

A method of assigning participants to conditions such that each participant has an equal chance of being placed into experimental groups. Assignment is the progress by which participants are out into either an experimental or a control group. It limits the effects of confounding variables based on differences between people. Using random assignment diminishes the chance that participants in the two groups differ in any meaningful way.

Random selection

A method of selecting a sample from a population. Every member of the population has an equal chance of being selected. Random selections increases the likelihood that the sample represents the population and that one can generalize the findings to the larger population

Stratified sampling

A process that allows a researcher to ensure that the sample represents the population on some criteria. For instance, if a researcher thinks that the participants of different racial groups might respond differently, he or she would want to make sure that each race is represented in the sample in the same proportion that is appears in the overall population.

Case study

A research method used to get a full, detailed picture of or participant or a small group of participants Allows researchers to get the richest possible picture of what they are studying, but the focus one one single individual or small group means that the findings cannot be generalized to a large population

Hypothesis

A statement that expresses a relationship between two variables. In an experimental hypothesis, the dependent variable depends on the independent variable. In other words, a change in the independent variable will produce a change in the dependent variable. For instance, consider the hypothesis that watching violent television programs makes people more aggressive. In this hypothesis, watching television violence is the independent variable since the hypothesis suggests that a change in television viewing will result in a change in the dependent variable aggression In testing a hypothesis, researchers manipulate the independent variable and measure the dependent variable

Correlation

A statistical measure of a relationship between toe variables. Correlation does not imply causation Can be either positive or negative. A positive correlation between two variables means that the presence of one variable predicts the presence of the other. A negative correlation means that the presence of one variable predicts the absence of the other. -1 is a perfect negative correlation +1 is a perfect positive correlation.

Theory

Aims to explain some phenomenon and allows researchers to generate testable hypothesis with the hope of collecting data that supports the theory. Hypotheses often grow out of theories

Operational definitions

An explanation of how variables are measured Two variables need to be operationally defined in the hypothesis "watching violent television programs makes people more aggressive" What programs will be considered violent? What behaviors will be considered aggressive?

Confounding variables

Any differences between the experimental and control conditions, except for the independent variable, that might affect the dependent variable. An experiment allows the researcher to manipulate the independent variable and control for confounding variables.

APA ethical guidelines for human research

Any type of academic research must first purpose the study to the ethics board or institutional review board (IRB) at the institution. Guidelines: Coercion Informed consent Anonymity/ confidentially Lack of risk Debriefing procedures

Hawthorne effect

Being selected to be in a group of people to participate in an experiment will affect the performance of that group, regardless of what is done to those individuals. Just selecting a sample of people and including them in an experiment will affect performance of the sample. Control groups help to control for the Hawthorne effect.

APA guidelines for animal research

Ethical psychological studies using animals must meet he following guidelines: Have a clear and scientific purpose Care for and house animals in a humane way. Acquire animals subjects legally. Design experimental procedures that employ the least amount of suffering feasible.

Reliability

Good research is both valid and reliable. Research is reliable when it can be replicated; it is consistent. If the researcher conducted the same research in the same way, the researcher would get similar results. A related concept is validity; research is valid when it measures what the researcher set out to measure; it's accurate

Validity

Good research is both valid and reliable. Research is valid when it measures what the researcher set out to measure; it is accurate. A related concept is reliability; research is reliable when it can be replicated; it is consistent

Survey method

Involves asking people to fill out surveys. Often used to gather opinions or attitudes and for correlational research. Response rate refers to the proportion of a surveyed group who respond to and return a survey.

Double-blind procedure

Method followed such that neither the participants nor the researcher are aware of who is in the experimental or control groups while the experiment is going on. Procedures control for both experimenter bias and participant bias

Naturalistic observation

Research method that involves observing participants in their natural habitats without interacting with them. The goal is to get a realistic and rich picture of the participants behavior. Cannot establish cause and effect relationships between variables

Basic research

Research that explores question that are of interest to psychologists but are not intended to have immediate, real-world applications. The other category of research is applied research, which is conducted in order to solve practical problems.

Applied research

Research that psychologists conduct to solve practical problems. Research that has clear, practical applications. The other category of research is basic research, which explains questions that are of interest to psychologists but are not intended to have immediate, real-world application.

Statistical significance

Scientists have decided that 5 percent is the cutoff for statistically significant results. This means that in a statistically significant experimental result, there is less than a 5 perfect chance that the results occurred by chance. Researchers use inferential statistics to determine whether results are statistically significant

Inferential statistics

Statistics that can determine whether or not findings can be applied to the larger population from which be sample was selected. .05 is the cut off for statistically significant results.

Participant bias or response bias

Tendency for subjects to behave in certain ways based on their perception of an experiment. Can be controlled for using a single- blind procedure (when participants do not know whether they are assigned to an experimental or control group) or a double-blind group (where neither the participants nor the researcher are aware of who is in the experiment or control groups while the experiment is going on.

Hindsight bias

Tendency upon hearing about research findings (and many other things) to think that they knew it all along. After an event occurs, it is relatively easy to explain why it happened. The goal of scientific research, however, is to predict what will happen in advance.

Population

The group from which a sample is selected. The population includes anyone or anything that could possibly be selected to be in the sample. The goal in selecting a sample is that is represents a larger population.

Sampling

The individuals on whom the research is conducted are called participants, and this process by which participants are selected is called sampling. To select a sample (the group of participants), first identify the population from which the sample will be selected. The population includes anyone or anything that could possibly be selected to be in the sample. The goal in selecting a sample is that is represents a larger population. Random selection means that every member of the population has an equal chance of being selected. Random selection increases the likelihood that the sample represents the population and that one can generalize the findings to the larger population.

Experiment

The only research method that can show a casual relationship. Allows the researcher to manipulate the independent variable and control for confounding variables A confounding variable is any difference between the experimental and control conditions, except for the independent variable, that might affect the dependent variable. Experiments compare at least two groups: an experimental group and a control group that differ based on the independent variable.

Assignment

The process by which participants are put into either an experimental or a control group. Random assignments means that each participant has an equal chance of being placed into any group. It limits the effects of confounding variables based on differences between people. Using random assignment diminishes the chance that participants in the two groups differ in any meaningful way.

Experimenter bias

The unconscious tendency for researchers to treat members of the experimental and Congo groups differently to increase the chance of confirming their hypothesis. Experimenter bias is not a conscious act. Is researchers purposely distort their data, it is called fraud, not experimenter bias. Using a double blind procedure can eliminate experimenter bias.

Measures of variability

Type of descriptive statistical measure that attempts to depict the diversity of distribution. Range, variance, and standard deviation are measures of variability