If all the points in a scatterplot lie on the least squares regression line, then what must the correlation coefficient r be?
A) only 1.0
B) only -1.0
C) either 1.0 or -1.0
D) only 100

Question

Quizplus · Accepted Answer

If all the points lie on the least squares regression line, then the correlation between these points must be perfect, indicating a linear relationship with either a positive or negative slope. 
A perfect positive relationship has a correlation coefficient of 1.0, while a perfect negative relationship has a correlation coefficient of -1.0. Thus, the answer is either 1.0 or -1.0.

If All the Points in a Scatterplot Lie on the Least