Exercise

# Standardizing Your Data

In the lecture, we saw that you can learn a lot about a dataset by creating the matrix \(A^TA\) from it. In this exercise, you'll do that with athletic data for players entering the National Football League college draft. The dataset `combine`

is loaded for you.

Instructions

**100 XP**

- Extract only the numerical elements of the data frame by taking only the 5th through 12th columns. Call this
`A`

(we cannot do math on the non-numerical components in columns 1 through 4). - Turn this data frame into a matrix by using the
`as.matrix()`

command. - Subtract the mean of each of the columns of the matrix.