What it does: The Pearson R correlation tells you the magnitude and direction of the association between two variables that are on an interval or ratio scale.

Where to find it: Under the Analyze menu, choose Correlations. Move the variables you wish to correlate into the "Variables" box. Under the "Correlation Coefficients," be sure that the "Pearson" box is checked off.

Assumption:
-Both variables are normally distributed. You can check for normal distribution with a Q-Q plot.

Hypotheses:
Null: There is no association between the two variables.
Alternate: There is an association between the two variables.

SPSS Output

Following is a sample output of a Pearson R correlation between the Rosenberg Self-Esteem Scale and the Assessing Anxiety Scale.

SPSS creates a correlation matrix of the two variables. All the information we need is in the cell that represents the intersection of the two variables.

SPSS gives us three pieces of information:
-the correlation coefficient
-the significance
-the number of cases (N)

The correlation coefficient is a number between +1 and -1. This number tells us about the magnitude and direction of the association between two variables.

The MAGNITUDE is the strength of the correlation. The closer the correlation is to either +1 or -1, the stronger the correlation. If the correlation is 0 or very close to zero, there is no association between the two variables. Here, we have a moderate correlation (r = -.378).

The DIRECTION of the correlation tells us how the two variables are related. If the correlation is positive, the two variables have a positive relationship (as one increases, the other also increases). If the correlation is negative, the two variables have a negative relationship (as one increases, the other decreases). Here, we have a negative correlation (r = -.378). As self-esteem increases, anxiety decreases.

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Susan Archambault
Psychology Department, Wellesley College

Created By: Nina Schloesser '02
Created On: July 31, 2000
Last Modified: July 31, 2000