Pearson's Correlation (1 of 3)
The correlation between two variables reflects the degree
to which the variables are related. The most common measure of
correlation is the Pearson Product Moment Correlation (called
Pearson's correlation for short). When measured in a
the Pearson Product Moment
correlation is designated by the Greek letter rho (ρ).
When computed in a sample, it is designated by the letter "r" and is
sometimes called "Pearson's r." Pearson's correlation reflects the
degree of linear relationship
variables. It ranges from +1 to -1. A correlation of +1 means that
there is a perfect positive linear relationship between variables.
The scatterplot shown on this page depicts such a relationship. It is
a positive relationship because high scores on the X-axis are
associated with high scores on the Y-axis.