14.23 Is the model fit in Exercise 14.16 useful? Carry out a test using a significance level of .10.

14.24 The accompanying Minitab output results from fitting the model described in Exercise 14.14 to data.

Predictor Coef Stdev t-ratio Constant 86.85 85.39 1.02 X1 -0.12297 0.03276 -3.75 X2 5.090 1.969 2.58 X3 -0.07092 0.01799 -3.94 X4 0.0015380 0.0005560 2.77 S = 4.784 R-sq = 90.8% R-sq(adj) = 89.4%

Analysis of Variance DF SS MS Regression 4 5896.6 1474.2 Error 26 595.1 22.9 Total 30 6491.7

a. What is the estimated regression equation?

b. Using a .01 significance level, perform the model utility test. (Hint: See Example 14.9.)

c. Interpret the values of R2 and se given in the output.