7. (19pts) Suppose the model Y = Bo + Bill + B242 + was fit to n = 100 data points. R command drop1 was applied, and the following results were obtained: 1 > sum( Im (Y ~ 1)$residuals^2 ) 2 [1] 33.60728 3 > dropl ( Im (Y ~ X1 + X2) ) Single term deletions 6 Model: 7Y ~ X1 + X2 Df Sum of Sq RSS AIC 12.531 10 X1 20.0324 32.564 11 X2 2.2299 14.761 (a) (10pts) Fill in the missing AIC values for , X1 and X2. If the AIC model selection criteria is used, can be model be improved? If so, how (what is the next step)? Justify your answer. (b) (9pts) Test Ho : 32 = 0 vs. H1 : 32 + 0 at the 5% level of significance. In your answer, please state clearly 7 (i) What is the value of the test statistic? (ii) What is the corresponding critical value and the reference distribution you use to find the critical value? (iii) What is your decision