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 R^2 is .5. When the two parents' education variables are dropped, the R^2 becomes .4. Are the parents' education variables significant at the 1% significance 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 R^2 values from two regressions).