Question

A) To test whether caffeine increases heart rate, a study was conducted with 10 male adults. Heart rate per minute was measured before and after drinking 3 cups of coffee containing 300 mg of caffeine. The before heart rates were measured while resting. The data was found to be normal and is given below. The standard deviation of the differences is s_d = 2.16. Assume that the scores are pairs of scores for ten subjects, and use a = 0.05 to test the claim. Give all 5 steps of a hypothesis test.

Subject            1          2          3          4          5          6          7          8          9          10

Before             62        62        57        63        76        59        56        58        60        63        

After               69        71        65        72        81        67        61        62        65        66

B) Suppose that in Part A, the information concerning the particular score of each subject was lost, and the scores are now treated like two independent samples, with equal variances. Test to see if the after group has a higher heart rate at a = 0.01. Use the information given below.            

Before             62        62        57        63        76        59        56        58        60        63        

After               69        71        65        72        81        67        61        62        65        66

                                    Mean              Standard Deviation

            Before             61.6                             5.64

            After               67.9                             5.80

Answer 1