14.24 Use the following information from a multiple regression analysis: = 1.2 n = 20 b= 4 b2 = 3 Sb = Sbx = 0.8 a. Which variable has the largest slope, in units of a t statistic? b. Construct a 95% confidence interval estimate of the population slope, Bi. c. At the 0.05 level of significance, determine whether each in- dependent variable makes a significant contribution to the regression model. On the basis of these results, indicate the in- dependent variables to include in this model