A student investigated the impact of Covid-19 pandemic on university students'

academic performance by comparing their GPAs in the semester before the pandemic started and the one right after that. The test result showed that the average difference in GPA was 2, and the p-value for the test was 0.02. Assess the statistical and practical significance of the test result if alpha = 0.05.

a. Is it statistically significant?

Yes or No, Why?

b. Is it practically significant?

Yes or No, Why?

The student also executed a regression to predict the average GPAs (the dependent variable, or Y) using the number of attendances (the independent variable, or X). The students expected that as the number of attendances increases the GPA increases.

a.State Ho and Ha with regards to 1:

Ho:

Ha:

b.The standard deviation of Y is 2.The square root of the sum of the squared residuals divided by n-2 equals 2, Does this suggest that the regression fits the data well? (No explanation required.)

Yes or No?

The student executes a hypothesis test with an alpha = 5% and rejects Ho for Ha.

a. What is the probability that the statistical conclusion is wrong?

b. If the student executed the same hypothesis test (with the above alpha) on different random samples of data 500 times, approximately how many times would it make the mistake of rejecting Ho when Ho is actually true in the population? Show your calculation below: