Obtain the added-variable plots for both predictors. Based on the added-variable plots, is log(ppgdp) useful after adjusting for pctUrban, and similarly, is pctUrban useful after adjusting for...

Obtain the added-variable plots for both predictors. Based on the added-variable plots, is log(ppgdp) useful after adjusting for pctUrban, and similarly, is pctUrban useful after adjusting for log(ppgdp)? Compute the estimated mean function with both predictors included as regressors, and verify the findings of the added variable plots.