When a common regression line for two groups is used to predict performance, but the individual regressions lines for the groups differ where they cross the Y axis, which one of the following problems may occur?
A) The performance of the group whose regression line crosses the y-axis at a higher point will be overpredicted.
B) The performance of the group whose regression line crosses the y-axis at a lower point will be overpredicted.
C) The performance of both groups will be overpredicted.
D) The performance of neither group will be overpredicted.

Question

Quizplus · Accepted Answer

When using a common regression line, the group whose individual regression line crosses the y-axis at a lower point will have its performance overpredicted because the common line assumes a higher intercept for both groups.

When a Common Regression Line for Two Groups Is Used