Dr.Kim thinks his regression equation is very accurate, but he wonders if perhaps the mean is just as good at predicting scores as the regression equation.He knows that the correlation coefficient (r) for the two variables is quite high, -0.82.Should Dr.Kim use the mean or the regression equation to predict scores? A) He should use the regression equation because the proportionate reduction in error (r²) is low. B) He should use the regression equation because the proportionate reduction in error (r²) is high. C) He should use the mean because the proportionate reduction in error (r²) is low. D) He should use the mean because the proportionate reduction in error (r²) is high.

Question

Quizplus · Accepted Answer

The proportionate reduction in error (r²) compares the variability in the dependent variable explained by the regression equation to the total variability in the dependent variable. A high proportionate reduction in error indicates that the regression equation is better at predicting scores than just using the mean. In this case, the high correlation coefficient suggests that the regression equation is likely to have a high proportionate reduction in error, indicating that it is a more accurate predictor than the mean. Therefore, Dr. Kim should use the regression equation.

DrKim Thinks His Regression Equation Is Very Accurate, but He