PSYC 2040 Lecture Notes - Descriptive Statistics, Standard Deviation
24 Jan 2014
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Document Summary
An educational psychologist examined the predictors of success for an. The predictors used were number of hours of sleep the night before the exam, and number of hours spent doing practice questions, in addition to the variance accounted for by number of hours spent reading the text. Table 1 indicates the mean and standard deviation for each predictor. The best independent predictor of grade was the number of hours spent reading the text (studying), which alone predicted 25% of the variance in exam performance ratings, sr2= . 25, t(497) = 13. 72, p < . 001. Sleep independently accounted for an additional 9%, sr2= . 09, t(497) = 8. 23, p < . 001, of the variance in exam performance ratings beyond studying alone, bringing the total percentage variance accounted for to 34%. When considering the proportion of variance in grade that is accounted for by both study and practice, r2= . 26, f(2, 497) = 88. 18, p < . 001, accounting for 26. 2% of variance.
