Answer
Not meaningful
Work Step by Step
If we add the matrices $A$ and $B$, on the first column of the sum we will have the total number of athletes who participated in each of the four NCAA sports from $2000$ to $2002$, which might be meaningful information.
On the second column of the sum we will have the sum of the average sizes of the teams for each of the four sports, which is a meaningless information!
What we can do is calculate $\frac{1}{2}(A+B)$, which would give us the average number of athletes and the average team size for each sport from $2000$ to $2002$.
