Psychology Research Methods Final Exam Review

Comprehensive vocabulary flashcards covering experimental designs, statistical measures, and threats to validity based on the final review notes.

Attrition (Mortality)

The dropout factor in an experiment, which can occur for reasons unrelated to the study (illness, death) or related to the experimental manipulation.

Repeated Measures design

An experimental design where the same individuals participate in all conditions and are repeatedly measured on the dependent variable.

Order effects

A disadvantage of repeated measures designs where the sequence of presenting treatments affects the dependent variable through practice, fatigue, or carryover effects.

Demand characteristics

Any feature of an experiment that might inform participants of the study's purpose or hypothesis, potentially influencing them to confirm that hypothesis.

Deception

A strategy to control for demand characteristics by making participants think the experiment is studying something else using cover stories or filler items.

Central Tendency

A descriptive statistic represented by a single number (mean, median, or mode) that tells how participants scored overall.

Mean

The average calculated by the sum of individual scores divided by the number of scores; used for interval and ratio scale data.

Median

The midpoint in a distribution with an equal number of scores above and below; used for ordinal, interval, and ratio scale data.

Mode

The most frequent score in a data set and the only choice for describing central tendency in nominal scale data.

Variance

The average squared deviation from the mean, describing how homogeneous or heterogeneous a set of data is.

Standard Deviation

A measure of variability indicating the average deviation of scores from the mean, calculated as the square root of the variance ($\sqrt{\text{variance}}$).

Chi-square ($\chi^2$)

A statistical test used to compare empirically observed values with theoretically expected values by summing squared deviations for each class.

Multiple Baseline design

A research design used when reversal of behaviors is impossible or unethical, measuring effectiveness across subjects, behaviors, or situations.

Interrupted time series design

A design that tracks an outcome variable over a long-term period before and after a specific intervention to identify trends and changes.

Factorial Design

An experimental design with more than one independent variable where all levels of each variable are compared with all levels of the other variables.

Main effect

The information yielded in a factorial design concerning the effect of each independent variable taken by itself.

Interaction

Refers to when the effect of one independent variable on the dependent variable depends on the particular level of another independent variable.

Pooled t-test

A statistical test used to compare the means of two groups, assuming similar variances and combining them into a single value.

ANOVA (Analysis of Variance)

A statistical test that compares the means of three or more groups by analyzing the ratio of systematic variance (between-group) to error variance (within-group).

External Validity

The extent to which study results can be generalized to other populations, locations, or times; often threatened by the use of specific samples like college students or volunteers.