Question

Sample Mean Sum of Squares Group Preparing to speak 96.8 23,655.2400 Speaking 101.5 21,099.8900 Listening 106.4 27,155.2500 After collecting the data, you analyze the data using an ANOVA. The results of your analysis are presented in the following ANOVA table. ANOVA Table Source of Variation SS df MS F Between Treatments 6,913.01 2 3,456.51 21.49 Within Treatments 71,910.38 447 160.87 Total 78,823.39 449 These findings are significant at a .05, which tells you that the difference is very unlikely to have occurred just by chance, but it does not tell you the size of the effect. A simple measure of the effect size is given by What is the formula for this measure of the effect size? SSpetween/SStotal MS between/MSwithin SSpetween/SSwithin MS petween/MStotal Based on the data given, the effect size is (Round your answer to two decimal places) The percentage of variability in the scores accounted for by the effect due to treatments is

Answer 1

a sample measure of effect size is given by $\eta$²

formula to be used : SSbetween/SStotal

the effect size is 6913.01/78823.39 =0.088

the percentage of variability in the scores accounted for by the effect due to treatment is 8.8 %