Accounting for Individual Differences

Flashcards about individual differences and their impact on experimental research, covering ANOVA, repeated measures ANOVA, and ANCOVA.

Individual Differences

Differences among individuals that can include age, gender, personality, and other psychological constructs, which can interfere with analyses in research.

Reducing Individual Differences

Selecting a more homogenous group, standardizing procedures and training subjects sufficiently.

Distinguishing Feature

Experimental designs deal with individual differences.

Repeated Measures Designs

Effectively eliminate group non-equivalence because individual differences are managed because all individuals are together in the same group.

Issue with Between Groups Variance

Individual differences contribute to between groups variance, and an IV effect observed may actually be due to individual differences.

Repeated Measures Design

Individual differences are removed by putting all participants in all conditions; no different groups, no chance for individual differences to be a problem.

Terminology Change

Independent Groups ANOVA: Between Groups, Within Groups; Repeated Measures ANOVA: Between Levels, Within Levels

Within Levels Variance

Due to errors in control, errors in measurement, individual differences, but not the IV/Treatment.

Repeated Measures ANOVA calculation

Between Levels Variance / Within Levels Variance

Sphericity

Violated when The variance of the difference scores between any two conditions is the same as the variance of the difference scores between any two other conditions.

Between Groups

Equalises groups on covariate, all participants are the same in covariate terms.

Within Groups

Reduces ‘noise’ by removing covariate differences.

Covariate

Variable correlated with dependent variable to control for