Suppose an instructor wants to see if there is an association between the amount of sleep students get and their ability to memorize words. The instructor asks her students to suggest ways to collect data to investigate this question.For each of the suggestions, identify:
• Whether the study is an experiment or an observational study
• Whether or not the data will be paired
a. Julia suggests the instructor have each student do two trials: one where they are told to get at least 7 hours of sleep the night before they take the memorization test and one where they are told to limit their sleep to at most 4 hours before they take the memorization test. The trials are a week apart and the students are randomly assigned which they do first.

b. Lindsey suggests half the students (chosen at random) should be told to get at least 7 hours of sleep before the memorization test and the other half should be told to get at most 4 hours of sleep before the test. They all then take the memorization test on the following day.

c. Mikaela suggests all students are given the memorization test and then are asked how many hours of sleep they got the night before.