Myers Psychology for AP 3e - Unit 02

hindsight bias

the tendency to believe, after learning an outcome, that one would have foreseen it. (Also known as the I-knew-it-all-along phenomenon.) (Myers Psychology for AP 3e p. 38)

theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events. (Myers Psychology for AP 3e p. 42)

hypothesis

a testable prediction, often implied by a theory. (Myers Psychology for AP 3e p. 42)

operational definition

a carefully worded statement of the exact procedures (operations) used in a research study. For example, human intelligence may be operationally defined as what an intelligence test measures. (Myers Psychology for AP 3e p. 42)

replication

repeating the essence of a research study, usually with different participants in different situations, to see whether the basic finding can be reproduced. (Myers Psychology for AP 3e p. 43)

case study

a descriptive technique in which one individual or group is studied in depth in the hope of revealing universal principles. (Myers Psychology for AP 3e p. 44)

naturalistic observation

a descriptive technique of observing and recording behavior in naturally occurring situations without trying to manipulate or control the situation. (Myers Psychology for AP 3e p. 45)

survey

a descriptive technique for obtaining the self-reported attitudes or behaviors of a particular group, usually by questioning a representative, random sample of the group. (Myers Psychology for AP 3e p. 47)

sampling bias

a flawed sampling process that produces an unrepresentative sample. (Myers Psychology for AP 3e p. 47)

population

all those in a group being studied, from which samples may be drawn. (Note: Except for national studies, this does not refer to a country's whole population.) (Myers Psychology for AP 3e p. 47)

random sample

a sample that fairly represents a population because each member has an equal chance of inclusion. (Myers Psychology for AP 3e p. 47)

correlation

a measure of the extent to which two factors vary together, and thus of how well either factor predicts the other. (Myers Psychology for AP 3e p. 50)

correlation coefficient

a statistical index of the relationship between two things (from −1.00 to +1.00). (Myers Psychology for AP 3e p. 51)

variable

anything that can vary and is feasible and ethical to measure. (Myers Psychology for AP 3e p. 50)

scatterplot

a graphed cluster of dots, each of which represents the values of two variables. The slope of the points suggests the direction of the relationship between the two variables. The amount of scatter suggests the strength of the correlation (little scatter indicates high correlation). (Myers Psychology for AP 3e p. 50)

illusory correlation

perceiving a relationship where none exists, or perceiving a stronger-than-actual relationship. (Myers Psychology for AP 3e p. 53)

regression toward the mean

the tendency for extreme or unusual scores or events to fall back (regress) toward the average. (Myers Psychology for AP 3e p. 53)

experiment

a research method in which an investigator manipulates one or more factors (independent variables) to observe the effect on some behavior or mental process (the dependent variable). By random assignment of participants, the experimenter aims to control other relevant factors. (Myers Psychology for AP 3e p. 54)

experimental group

in an experiment, the group exposed to the treatment, that is, to one version of the independent variable. (Myers Psychology for AP 3e p. 54)

control group

in an experiment, the group not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment. (Myers Psychology for AP 3e p. 54)

random assignment

assigning participants to experimental and control groups by chance, thus minimizing preexisting differences between the different groups. (Myers Psychology for AP 3e p. 54)

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. (Myers Psychology for AP 3e p. 55)

placebo

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. (Myers Psychology for AP 3e p. 55)

independent variable

in an experiment, the factor that is manipulated; the variable whose effect is being studied. (Myers Psychology for AP 3e p. 55)

confounding variable

a factor other than the factor being studied that might influence a study's results. (Myers Psychology for AP 3e p. 56)

dependent variable

in an experiment, the outcome that is measured; the variable that may change when the independent variable is manipulated. (Myers Psychology for AP 3e p. 56)

validity

the extent to which a test or experiment measures or predicts what it is supposed to. (See also content validity and predictive validity.) (Myers Psychology for AP 3e pp. 56, 636)

informed consent

giving potential participants enough information about a study to enable them to choose whether they wish to participate. (Myers Psychology for AP 3e p. 62)

debriefing

the postexperimental explanation of a study, including its purpose and any deceptions, to its participants. (Myers Psychology for AP 3e p. 62)

descriptive statistics

numerical data used to measure and describe characteristics of groups. Includes measures of central tendency and measures of variation. (Myers Psychology for AP 3e p. 66)

histogram

a bar graph depicting a frequency distribution. (Myers Psychology for AP 3e p. 66)

mode

the most frequently occurring score(s) in a distribution. (Myers Psychology for AP 3e p. 67)

mean

the arithmetic average of a distribution, obtained by adding the scores and then dividing by the number of scores. (Myers Psychology for AP 3e p. 67)

median

the middle score in a distribution; half the scores are above it and half are below it. (Myers Psychology for AP 3e p. 67)

skewed distribution

a representation of scores that lack symmetry around their average value. (Myers Psychology for AP 3e p. 67)

range

the difference between the highest and lowest scores in a distribution. (Myers Psychology for AP 3e p. 68)

standard deviation

a computed measure of how much scores vary around the mean score. (Myers Psychology for AP 3e p. 68)

normal curve (normal distribution)

a symmetrical, bell-shaped curve that describes the distribution of many types of data; most scores fall near the mean (about 68 percent fall within one standard deviation of it) and fewer and fewer near the extremes. (Myers Psychology for AP 3e pp. 68, 635)

inferential statistics

numerical data that allow one to generalize—to infer from sample data the probability of something being true of a population. (Myers Psychology for AP 3e p. 70)

statistical significance

a statistical statement of how likely it is that an obtained result occurred by chance. (Myers Psychology for AP 3e p. 71)