Exercise 4 Page 196

A correlation coefficient tells us two things:

1. The strength of the correlation: the correlation is strong if r is close to |1| and weak if it is close to 0.
2. If the correlation is positive or negative.

Let's look at what each of the given values of r tells us.

The only correlation coefficient that does not match the features of another is r=-0.09. It is an extremely weak fit because less than 10 % of the data points can be approximated with the line of fit. The other three values for r are extremely strong correlations, as almost all the data points can be explained by the line of fit.