Chapter 4.1, Problem 4.20E

(a)

To determine

To explain in words what r says given in the question.

Explanation of Solution

In the question r says the relationship is moderately strong close to $0.5$ and has to be negative association as r is negative.

(b)

To determine

To suggest an explanation for this relationship.

Explanation of Solution

The explanation to this is that the more siblings somebody has, the lesser time that child spends studying.