Model 1: lm(Y ~ X1 + X2) Model 2: lm(Y ~ X1 + X2 + X3) Model 3: lm(Y ~ X1 + X2 + .... X15)

Write R code to do a bootstrap with 20 resamples. Compute the MSPE for each model and each round of bootstrap. Then summarize the MSPE via a boxplot of bootstrap error