Use the following information from a multiple regression analysis: n=25 b1=5 b2=10 Sb1 =2 Sb2 =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, β1. 

c) At the 0.05 level of significance, determine whether 
each independent variable makes a significant contribution to the regression model. On the basis of these results, indicate the independent variables to include in this model.