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.
-Both variables are normally distributed. You can check for normal distribution with a Q-Q plot.
Null: There is no association between the two variables.
Alternate: There is an association between the two variables.
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 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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Psychology Department, Wellesley College
Created By: Nina Schloesser '02
Created On: July 31, 2000
Last Modified: July 31, 2000