Computing Pearson's Correlation Coefficient
Next section: Example values
The formula for Pearson's correlation takes
on many forms. A commonly used formula is shown on the right. The formula
looks a bit
complicated, but taken step by step as shown in the
numerical
example, it is really quite simple.

A simpler looking formula can be used if the numbers are
converted
into z scores:
where z
x is the variable X converted into z scores and z
y
is the variable Y converted into z scores.
Next section: Example values