Question

1. Drew wondered if the average age of students in AP Statistics classes in his high school is under 18. He randomly selected 20 AP Statistics students in his school, and the data set is given below. Using the information from a previous survey, he has concluded that the population standard deviation for the age of AP Statistics students in his school is 1.23. Assume that the ages of students in AP Statistics classes in this high school are normally distributed. Use Excel to test whether the true age of AP Statistics students in his school is under 18. Identify the p-value, rounded to three decimal places.

Student Ages
17
19
18
17
15
18
16
17
17
16
17
18
19
17
18
18
16
18
18
15

Answer 1

Claim:  The true age of AP Statistics students in his school is under 18.

The null and alternative hypothesis is

Level of significance = 0.05

By using excel we have to test the above hypothesis.

Enter data into excel.

Here population standard deviation is known so we have to use z-test.

Use command =ZTEST(Select data,18,1.23)

We get P-value = 1 - 0.9982 = 0.0018

P-value < 0.05 we reject null hypothesis.

Conclusion:

The true age of AP Statistics students in his school is under 18.