In a multiple regression model using 400 students to explain college grade point average, the following explanatory variables and a constant term equal to 1 are initially included in the regression: high school GPA, ACT score, number of credits completed, mother's years of education, and father's years of education. The R2 is .5. When the two parents' education variables are dropped, the R2 becomes .4. Are the parents' education variables signifcant at the 1% signifcance level? Specifically, state the null and alternative hypotheses, relevant test statistic, critical value, and a short explanation for how you reached your conclusion. (Hint: remember that the lectures and the book both explain how to conduct an F-test of joint significance using R2 values from two regressions).