PSYC 3370 Study Guide - Final Guide: Internal Validity, Wine Tasting, Meta-Analysis
Document Summary
Within-group variance: participants assigned to same treatment condition respond diff due to individual diffs, differences within a treatment are considered to reflect experimental error, within-group variance provides an estimate of experimental error. Calculating the variance estimates: numerical values representing these sources of variance are called mean squared deviations (mean squares, ms, we need to calculate these measures of variance to complete anova of ! Ex: for subject 1 in film a group. Total deviation: the deviation of each score from the grand mean, td = individual score - grand mean, if positive, better than the average. Within-groups deviation: the deviation of each score from the group mean, wd = individual score - group mean, if positive, better than the average, due to individual diffs, estimate of error. Ex: wd = 9 - 6. 25 = 2. 75. Between-groups deviation: the deviation of a group mean from the grand mean, bd = group mean - grand mean.