An educational psychologist is testing the discriminant validity of a new measure of numerical learning difficulties. He gives his measure to a group of students along with another measure of verbal learning difficulties, which he predicts should not be strongly related to numerical learning difficulties. Which of the following correlations would the psychologist hope to find in order to establish discriminant validity?
A)r = 1.0
B)r = −1.0
C)r = 0.83
D)r = −0.18

Question

Quizplus · Accepted Answer

The psychologist would hope to find a low, negative correlation between the measure of numerical learning difficulties and the measure of verbal learning difficulties in order to establish discriminant validity. Therefore, the best choice is D, which shows a negative correlation, but not too strong as to suggest that the two measures are measuring the same construct. A perfect negative correlation (B) would mean that the two measures are inversely related and measuring the same construct. A perfect positive correlation (A) would mean that the two measures are highly related and measuring the same construct. A moderate positive correlation (C) would suggest that there is some shared variance between the measures, rather than complete discriminant validity.

An Educational Psychologist Is Testing the Discriminant Validity of a New