Correlating the scores of 50 students on two tests, an investigator found that the sum of the z-score cross-products was 20.The Pearson's product moment coefficient in this case is:
A) impossible to compute with the information given.
B) .02.
C) .20.
D) .40.
E) None of these are true.

Question

Quizplus · Accepted Answer

The sum of the z-score cross-products is equal to n times the Pearson's product moment coefficient. Therefore, we can solve for the coefficient by dividing the sum by the number of students: 20/50 = 0.4. Therefore, the Pearson's product moment coefficient is 0.4, which corresponds to answer choice D.

Correlating the Scores of 50 Students on Two Tests, an Investigator