The effects of caffeine on the body have been extensively studied. In one experiment1, researchers examined whether caffeine increases the rate at which people are able to tap their fingers. Twenty students were randomly divided into two groups of

Question attached

Answer and explanation:

Here we would use the two sample t test. In finding the hypotheses for a two sample t test we test the sample mean of one group against the other group to determine if there is a statistical difference or they are equal. We have this to compare the mean finger tapping rate of the two groups being tested in the question. Our null and alternative hypotheses here are:

H0: u1 = u2 null hypothesis

H1: u1 > u2 alternative hypothesis

Where u1 and u2 are the sample means for each group in the caffeine experiment

3; 9 is 8 to -4

step-by-step explanation: