If we are interested in whether students at this high school are getting too little

QUESTION:

Section I: Multiple Choice Choose the best answer.

Questions 28  and 29 refer  to the following  setting.  According  to  sleep  researchers,  if  you  are  between  the  ages of 12 and 18 years old, you need 9 hours of sleep to be fully functional. A simple random sample of 28 students was chosen from a large high school, and these students were asked how much sleep they got the previous night. The mean of the responses was 7.9 hours, with a standard deviation of 2.1 hours.

If we are interested in whether students at this high school are getting too little sleep, which of the following represents the appropriate null and alternative hypotheses?

(a) \(H_{0}: \ \mu=7.9\) and \(H_{a}: \ \mu<7.9\)

(b) \(H_{0}: \ \mu=7.9\) and \(H_{a}: \ \mu \neq 7.9\)

(c) \(H_{0}: \ \mu=9\) and \(H_{a}: \ \mu \neq 9\)

(d) \(H_{0}: \ \mu=9\) and \(H_{a}: \ \mu<9\)

(e) \(H_{0}: \ \mu \leq 9\) and \(H_{a}: \ \mu \geq 9\)