The principal of Berkeley High School has read that based on

The principal of Berkeley High School has read that based on the national norm, a high school student will miss 15 days of class per school year. He is curious if the number of day missed by the students in his school is different from the national norm. He takes a random sample of 25 students\' attendence records, and finds that for this sample the average number of school days missed per year is 17 and the standard deviation is 8. What is the approximate p-value for a two-tailed test?

The principal of Berkeley High School has read that, on average, a high school student will miss 15 days of class per school year. He is curious if his high school is letting students have too many sick days, so he takes a random sample of 40 students\' attendence records, and finds that the sample average is 22 days missed with a sample standard deviation of 8 days. If he decides to test the hypothesis H0: mu = 15 days against Ha: mu not = 15 days using this sample, what distribution does he use and what p-value does he find?

Select one:

a. He uses the T distribution with 40 degrees of freedom, and finds a p-value of less than 0.05.

b. He uses the T distribution with 40 degrees of freedom, and finds a p-value greater than 0.01.

c. He uses the T distribution with 39 degrees of freedom, and finds a p-value between 0.01 and 0.05.

d. He uses the T distribution with 39 degrees of freedom, and finds a p-value of less than 0.05.

e. He uses the T distribution with 29 degrees of freedom, and finds a p-value greater than 0.01.

Solution

d. He uses the T distribution with 39 degrees of freedom, and finds a p-value of less than 0.05.