Fit the following two resistant regressions, in each case plotting the residuals against Year. Compare, also, normal probably plots for the two sets of residuals. (a) Repeat the calculations several...

Fit the following two resistant regressions, in each case plotting the residuals against Year.

Compare, also, normal probably plots for the two sets of residuals.

(a) Repeat the calculations several times. Comment on the extent of variation, from one run to the next, in the regression coefficients.

(b) Based on examination of the residuals, which regression model seems more acceptable: nraw.lqs or north.lqs?

(c) Compare the two sets of regression coefficients. Can you explain why they are so very different?