Weisberg (1985) gives the data, shown in Appendix D.17, that were collected by another physicist, Hooker, who conducted an experiment similar to that of Forbes. These data were collected at higher altitudes than the Forbes data

a. Combine these data with the reduced, Forbes data, fit the linear model, and examine the (xy)-scatter-plot and the Gr)-residual plot to see if the combination is justified, if the same non-linear pattern is present and if there are any outlying cases.

b. Use the Box-Cox and Atkinson methods to see if the logarithmic transformation is justified.

c. Use the Box-Tidwell method to see if a transformation on Tx is indicated. 3.10 In the study of polymers used in making plastics, an essential relation is that of the intrinsic velocity (IV) and molecular weight (MW). Data for one study are shown in Appendix D.16.

a. Plot the data and determine the regression of IV on MW. Examine the residual plot and the ggplot.

b. Use the Box-Cox or Atkinson method to determine a transformation on IV.

c. Regress log(IV) on MW and examine the residual and plots.

d. Use the Box-Tidwell method to determine a transformation on MW for the model in part (c).

e. Regress log(IV) on log(MW) and examine the residual and qq plots.