User Guide

228
Chapter 11
Correlating
Variables
The Correla
te submenu on the Analyze menu provides measures of association for
two or more numeric variables.
The examples in this topic use the data file Employee data.sav.
Bivariate Correlations
The Bivariate Correlations procedure computes statistics such as Pearson’s
correlation coefficient. Correlations measure how variables or rank orders are related.
Correlati
on coefficients range in value from –1 (a perfect negative relationship) and
+1 (a perfect positive relationship). A value of 0 indicates no linear relationship.
For example, you can use Pearson’s correlation coefficient to see if there is a
strong lin
ear association between Current Salary (salary) and Beginning Salary
(salbegin) inthedatafileEmployee data.sav.
Partial Co
rrelations
The Parti
al Correlations procedure calculates partial correlation coefficients that
describe the relationship between two variables while adjusting for the effects of one
or more additional variables.
You can es
timate the correlation between Current Salary (salary) and Beginning
Salary (salbegin), controlling for the linear effects of Months since Hire (jobtime)
and Previous Experience (prevexp). The number of control variables determines the
order of
the partial correlation coefficient.
To carry
out this Partial Correlations procedure, use the following steps:
E Open th
e Employee data.sav file. It is usually in the directory where SPSS is installed.