A researcher computes a Pearson product moment correlation that yields an r value of .50. Which of the following is true?
A) The effect size using r is large
B) 25% of the variance between the study's two variables is common to both
C) 75% of the variance between the study's two variables is unexplained
D) All of the above

Question

Quizplus · Accepted Answer

A) An r value of .50 indicates a moderate to large effect size using the guidelines proposed by Cohen (1988). 
B) To calculate the proportion of shared variance, you square the correlation coefficient. In this case, .50 squared equals .25, indicating that 25% of the variance is common to both. 
C) The remaining 75% of the variance is unexplained or unique to each variable.

A Researcher Computes a Pearson Product Moment Correlation That Yields