Suppose that a researcher estimated a regression model, Y = 0 + 1X1 + 2X2 + 3X1 2 + 4X2 2 + , where Y is income, X1 is age and X2 is years of education.Suppose further that he estimated the model with a sample of 60 individuals and wanted to test if the coefficients for the two quadratic terms are both equal to zero.Which of the following critical value should he use to test this joint hypothesis at 5% significance level