A) LOOCV is not random because you fit all n possible models that leave out a single observation. k-fold CV is random because we randomly split the data into k chunks. How many models would we need to fit to exhaustively obtain MSPE for every excluded chunk of size n/k? b) For the data-set "Puromycin", manually carry out LOOCV to compare two models predicting rate, one with conc and one with conc and state. (Don't forget that you can subset data via something like data[1,] to only look at the first row, or data(-1,] to remove the first row. You may find a loop (help(for)) useful but not necessary.) Submit the output of your R. Markdown. You should clearly report the RMSPELOO for both models and determine which model LOOCV chooses.