Chapter 4.2, Problem 63E

To determine

To calculate: The product matrix $\left[\begin{array}{cc}-1& 1\end{array}\right]P$ when thinking of the provided table as a labeled $2\times 2$ matrix $P$. The U.S. per capita consumption of yogurt and ice cream in $1983$ and $2013$ was as:

$\begin{array}{ccc}& 1983& 2013\\ \text{Yogurt}\left(\text{pounds}\right)& 3.2& 14.9\\ \text{Ice creame}\left(\text{pounds}\right)& 26.3& 20.1\end{array}$

Also mention what does this product represent.