Introductory Econometrics: A Modern Approach 6th Edition by Jeffrey M Wooldridge

Exercise 11

Suppose that between their first and second years in college, 400 students are randomly selected and given a university grant to purchase a new computer. For student i, yi denotes the change in GPA from the first year to the second year. If the average change is  with standard deviation s = 1.27, is the average change in GPAs statistically greater than zero?

Step 1 of 2

In second year, university grants their 400 students to buy new computers for their self. It is given thatdenotes the average change in GPA from first year to second year. Consider that: