14.29 The article “The Undrained Strength ofSome Thawed Permafrost Soils” (Canadian Geotechnical Journal [1979]: 420–427) contained the accompanying data (see page 830) on y shear strength of sandy soil (kPa), x1 depth (m), and x2 water content (%).

The predicted values and residuals were computed using the estimated regression equation y^ 5 2151.36 2 16.22x1 1 13.48x2 1 .094x3 2 .253x4 1 .492x5 where x3 5 x21

, x4 5 x22

, and x5 5 x1x2.

a. Use the given information to compute SSResid, SSTo, and SSRegr.

b. Calculate R2 for this regression model. How would you interpret this value?

c. Use the value of R2 from Part

(b) and a .05 level of significance to conduct the appropriate model utility test.

Transcribed Image Text:

y X1 X2 Predicted y Residual 14.7 8.9 31.5 23.35 -8.65 48.0 36.6 27.0 46.38 1.62 25.6 36.8 25.9 27.13 -1.53 10.0 6.1 39.1 10.99 -0.99 16.0 6.9 39.2 14.10 1.90 16.8 6.9 38.3 16.54 0.26 20.7 7.3 33.9 23.34 -2.64 38.8 8.4 33.8 25.43 13.37 16.9 6.5 27.9 15.63 1.27 27.0 8.0 33.1 24.29 2.71 16.0 4.5 26.3 15.36 0.64 24.9 9.9 37.8 29.61 -4.71 7.3 2.9 34.6 15.38 -8.08 12.8 2.0 36.4 7.96 4.84