A social scientist learns, upon analyzing her data, that the correlation between a subject's hours of television watched and their score on a test that measures propensity to violence is r = 0.3. One way to use r is to compute the percent of the variation in the violence test score that can be explained by the straight-line relationship between that violence test score and hours of television watched. This percent is about
A) 30%.
B) 70%.
C) 9%.
D) 21%.
E) 7%.

Question

Quizplus · Accepted Answer

The square of the correlation coefficient (r²) represents the proportion of variability in the violence test score that can be explained by the relationship with hours of television watched. In this case, r² = 0.3² = 0.09, which means that only 9% of the variation in the violence test score can be explained by the hours of television watched.

A Social Scientist Learns, Upon Analyzing Her Data, That the Correlation