Suppose the correlation between heights of fathers and the heights of their (adult) sons is r = 0.49. All heights are measured in inches.

Question

• Which if the following is true? 

a.49% of all sons are taller than their fathers.
b.sons are, on the average, taller than their fathers.
c.taller-than-average fathers tend to have taller-than-average sons.
d.taller-than-average fathers tend to have shorter-than-average sons. e/
nothing can be concluded unless one knows the regression equation form.

 

 

 

Answer 1

Easy! Unlike a regression formula, the correlation coefficient  doesn't dictate the details of one variable with respect to the other; it only clues us in as to how much the two variable walk in lockstep, and whether they go in the same direction. A positive variable means the two move in the same direction. We have already eliminated A and B because they provide specifics we do not have. That leaves C and D. Since D claims the variables work in opposite directions, that leaves your final answer:

C