Suppose you want to study the number of hours of sleep full-time college students at your college get each evening. To do so, you obtain a list of full-time students at your college, obtain a simple random sample of ten students, and ask each of them to disclose how many hours of sleep they obtained the most recent Monday.

(a) What is the population of interest in this study? What is the sample?

(b) Explain why number of hours of sleep in this study is a random variable.

(c) After you obtain your ten observations, you compute the mean number of hours of sleep. Is this a statistic or a parameter? Why?

(d) Is the mean number of hours computed in part (c) a random variable? Why? If it is a random variable, what is the source of variation? How does the source of variation in this study differ from that of Problem 40?