Which of the four correlation coefficients below best exemplifies a moderate relationship showing less back pain in people who exercise more frequently? a. 0.7 b. - 0.5 c. - 0.2 d. 0.4

Answer: d. 0.4

Step-by-step explanation:

We know that the correlation coefficient is a r-value measure of the strength of the linear relationship between two quantities.

When the value of correlation coefficient (r-value) lies between - 0.5 to - 0.3 or 0.3 to 0.5, then it indicates that there is moderate association.

From all the given four correlation coefficients, 0.4 is the best value that exemplifies a moderate relationship showing less back pain in people who exercise more frequently since it lies between 0.3 and 0.5.

Hence, d is the correct option.