1. The scatterplot and least-squares regression line for predicting Y from X is given in the figure below for the following pairs of scores from a pretest and posttest:

Keith Bill Charlie Brian Mick Pretest (X) 8 9 4 2 2 Posttest (Y) 10 6 8 5 1 prediction correlation and prediction regression line prediction error line of best fit independent variable dependent variable predicted score error sum of squares least-squares criterion regression equation slope intercept regression toward the mean total variation total sum of squares explained variation unexplained variation standard error of estimate assumption of homoscedasticity post hoc fallacy 11 10 9

8 7

6 5

4 3

2 1

1 2 3 4 5 6 7 8 9 10 11 X: Quiz Y: Quiz 168 Chapter 8 Regression and Prediction