Question

Opinions about whether caffeine enhances test performance differ. You design a study to test the impact of drinks with different caffeine contents on students' test-taking abilities. You choose 21 students at random from your introductory psychology course to participate in your study. You randomly assign each student to one of three drinks, each with a different caffeine concentration, such that there are seven students assigned to each drink. You then give each of them a plain capsule containing the precise quantity of caffeine that would be consumed in their designated drink and have them take an arithmetic test 15 minutes later. The students receive the following arithmetic test scores: Cola 2.9 85 86 82 75 Coffee 13.4 92 87 80 89 96 83 92 Water Caffeine Content (mg/oz) 2X2 141,479 G 1,715 N 21 k=3 78 72 72 64 81 82 78 87 T1-537 T2=559 T3-619 SS1 381.43 SS 338.86 SS 185.71 n2 7 M 76.7143 M2 79.8571 M 88.4286 n37 You plan to use a the null hypothesis? n ANOVA to test the impact of drinks with different caffeine contents on students' test-taking abilities. What is O The population mean test scores for all three treatments are not all equal O The population mean test scores for all three treatments are different. he population mean test score for the water population is different from the population mean test score for the cola population O The population mean test scores for all three treatments are equal Calculate the degrees of freedom and the variances for the following ANOVA table: df MS Source

Answer 1