Most sleeping pills reduce the period of dreaming sleep, also known as rapid eye movement (REM) sleep. You want to validate the claims of a new sleeping pill, which is advertised as not affecting REM sleep at all. You randomly select two groups of participants. Group 1 receives a placebo, and group 2 receives the recommended dosage of the new sleeping pill. REM sleep is monitored in a sleep lab during the course of one night's sleep, and the total number of minutes spent in REM are counted for each subject. Table 1 below summarizes the results.
a) What test should you use to analyze these results, and why? Will you use a one-tail or two-tailed test, and why?
b) What significance level will you use, and why?
c) What are the results of your analysis? Did your IV have a significant effect on your DV? Show your work.