For the following stories from Questions #1-4, which would be most appropriately calculated using the Normal (Z) distribution?

1. Is there a difference in the population mean number of years required to earn a bachelor's degree for men and for women?
2. Estimate the average number of years it takes students in the population to earn a bachelor's degree if the population standard deviation is known to be 1.25 year.
3. Is there a difference in the population mean number of years required to earn a bachelor's degree for students majoring in education, nursing, science, and public health?
4. A sample of students had their GPAs recorded at the end of their freshmen year and again at the end of their junior year of college to see if there is a significant decrease in GPA as students in the population take more challenging classes in their majors.

Group of answer choices

a. #4

b. None of them

c. #2

d. #1

e. #3