Myers' Psychology 4th edition | Unit 0 Vocabulary
histogram
a bar graph depicting a frequency distribution
operational definition
a carefully worded statement of the exact procedures (operations) used in a research study. EX: If a psychologist is studying "aggression", an operational definition might be: The number of times a person hits, yells, or threatens someone during a 30-minute observation period. This specific definition allows researchers to consistently measure aggression in the study.
standard deviation
a computed measure of how much scores vary around the mean score
placebo
a fake drug used in the testing of medication
sampling bias
a flawed sampling process that produces an unrepresentative sample
scatterplot
a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggest the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation) / positive \ negative - no relationship
correlation
a measure of the extent to which two factors vary together, and thus how well either factor predicts the other EX: Researchers find a positive correlation between the number of hours students study and their exam scores. The more hours they study, the higher their scores tend to be. However, this doesn't mean studying more causes better scores, just that the two variables are related.
survey
a non-experimental technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group
case study
a non-experimental technique in which one individual or group is studied in depth in the hope of revealing universal principles
naturalistic observation
a non-experimental technique of observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation
skewed distribution
a representation of scores that lack symmetry around their average value
qualitative research
a research method that relies on in-depth, narrative data that are not translated into numbers
quantitative research
a research method that relies on quantifiable, numerical data
random sample
a sample that fairly represents a population because each member has an equal chance of inclusion
correlation coefficient
a statistical index of the relationship between two things (from -1 to +1) +1.0 indicates a perfect positive correlation (as one variable increases, the other increases). -1.0 indicates a perfect negative correlation (as one variable increases, the other decreases). 0 indicates no correlation (no relationship between the variables).
meta-analysis
a statistical procedure that averages the results of multiple studies to reach an overall conclusion
statistical significance
a statistical statement of how likely it is that a result occurred by chance, assuming there is no difference between the population being studied
hypothesis
a testable prediction, often implied by a theory
population
all those in a group being studied, from which samples may be drawn
double-blind procedure
an experimental procedure in which both the research participants and the research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo. Commonly used in drug-evaluation studies.
single-blind procedure
an experimental procedure in which the research participants are ignorant (blind) about whether they have received the treatment or a placebo.
theory
an explanation using an integrated set of principles that organizes observations and predicts behaviors or events
variable
anything that can vary and is feasible and ethical to measure
random assignment
assigning participants to experimental and control conditions by chance, thus minimizing preexisting differences between those assigned to the different groups
experimenter bias
bias caused when researchers may unintentionally influence results to confirm their own beliefs
social desirability bias
bias from people's responding in ways they presume a researcher expects or wishes EX: In a survey about alcohol consumption, a participant may underreport how much they drink because they want to appear more responsible or healthier, even though their actual drinking habits are higher. This is an example of social desirability bias, where the respondent answers in a way they believe will be more socially acceptable.
self-report bias
bias when people report their behavior inaccurately
effect
experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert substance or condition, which the recipient assumes is an active agent
informed consent
giving potential participants enough information about a study to enable them to choose whether they wish to participate
inferential statistics
numerical data that allow one to generalize- to infer from sample data the probability of something being true of a population
descriptive statistics
numerical data used to measure and describe characteristics of groups. Includes measures of central tendency and measures of variation.
illusory correlation
perceiving a relationship where none exists, or perceiving a stronger-than-actual relationship
mean
the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores
range
the difference between the highest and lowest scores in a distribution
validity
the extent to which a test measures or predicts what it is supposed to
median
the middle score in a distribution; half the scores are above it and half are below it
mode
the most frequently occurring score(s) in a distribution
percentile rank
the percentage of scores that are lower than a given score
falsifiable
the possibility that an idea, hypothesis, or theory can be disproven by observation or experiment
debriefing
the postexperimental explanation of a study, including its purpose and any deceptions, to its participants
effect size
the strength of a relationship between two or more variables. The larger the effect size, the more one variable can be explained by the other
normal curve
the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes. Most scores fall near the average, and fewer and fewer scores lie near the extremes.
regression toward the mean
the tendency for extreme or unusual scores or events to fall back (regress) toward their average.
overconfidence
the tendency to be more confident than correct—to overestimate the accuracy of our beliefs and judgments.
hindsight bias (I-knew-it-all-along phenomenon)
the tendency to believe, after learning an outcome, that one would have foreseen it
critical thinking
thinking that does not blindly accept arguments and conclusions. Rather, it examines assumptions, discerns hidden values, evaluates evidence, and assesses conclusions.
experiment
A research method in which an investigator manipulates one or more factors (independant variable) to observe the effect on some behavior or mental process (dependent variable)
experimental group
In an experiment, the group that is exposed to the treatment, that is, to one version of the independent variable.
cofounding variable
in an experiment, a factor other than the independent variable that might influence a study's results
independent variable
in an experiment, the factor that is manipulated; the variable whose effect is being studied
control group
in an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment.
dependent variable
in an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated
replication
repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding extends to other participants and circumstances
peer reviewers
scientific experts who evaluate a research article's theory, originality, and accuracy
