Reviewers from the Oregon Evidence-Based Practice Center at the Oregon Health and Science University investigated the effectiveness of prescription drugs in assisting people to fall asleep and stay asleep. The Oregon reviewers, led by Susan Carson, M.P.H., concluded that Sonata was better than Ambien at putting people to sleep quickly, whereas patients on Ambien slept longer and reported having a better quality sleep than those taking Sonata. Samples taken by Carson and her associates are contained in a file entitled Shuteye. The samples reflect an experiment in which individuals were randomly given the two brands of pills on separate evenings. Their time spent sleeping was recorded for each of the brands of sleeping pills.

a. Does the experiment seem to have dependent or independent samples? Explain your reasoning.

b. Do the data indicate that the researchers were correct? Conduct a statistical procedure to determine this.

c. Conduct a procedure to determine the plausible differences in the average number of hours slept by those taking Ambien and Sonata.