A theory suggests that X should have a positive effect on Y. Upon analyzing a set of data, the correlation between X and Y is 0.55, and remains just as strong when Z is controlled. What does this tell us about the theory in question?
A) The theory was on the right track, but had the direction of the effect reversed.
B) The theory is proven correct.
C) The theory is supported, but other control variables need to be considered.
D) Nothing can be learned about the theory.

Question

Quizplus · Accepted Answer

The positive correlation of 0.55 supports the theory that X has a positive effect on Y. The fact that this correlation remains strong when controlling for Z suggests that Z does not confound the relationship, but other variables might still need to be considered to fully validate the theory.

A Theory Suggests That X Should Have a Positive Effect