Calculation for the Test of the Difference
Between Two Independent Correlation Coefficients
quantpsy.org
© 2010-2014,
Kristopher J. Preacher

Calculation for the test of the difference between two independent correlation coefficients
Kristopher J. Preacher (Vanderbilt University)

How to cite this page

This web utility may be cited in APA style in the following manner:

Preacher, K. J. (2002, May). Calculation for the test of the difference between two independent correlation coefficients [Computer software]. Available from http://quantpsy.org.

The purpose of this page

This interactive calculator yields the result of a test of the hypothesis that two correlation coefficients obtained from independent samples are equal. The result is a z-score which may be compared in a 1-tailed or 2-tailed fashion to the unit normal distribution. By convention, values greater than |1.96| are considered significant if a 2-tailed test is performed.

How it's done

First, each correlation coefficient is converted into a z-score using Fisher's r-to-z transformation. Then, making use of the sample size employed to obtain each coefficient, these z-scores are compared using formula 2.8.5 from Cohen and Cohen (1983, p. 54).

How to use this page

Enter the two correlation coefficients, with their respective sample sizes, into the boxes below. Then click on "calculate." The p-values associated with both a 1-tailed and 2-tailed test will be displayed in the "p" boxes.

r
n
Output:
Sample 1:
z-score:
Sample 2:
1-tail p:
2-tail p:
Status:

References

Cohen, J., & Cohen, P. (1983). Applied multiple regression/correlation analysis for the behavioral sciences. Hillsdale, NJ: Erlbaum.

Acknowledgments

Original version posted May, 2002. Free JavaScripts provided by The JavaScript Source and John C. Pezzullo.