Pearson correlation

Home > Statistics Every Writer Should Know > The Stats Board > Discusssion

Pearson correlation
Message posted by A. Kutlik on March 23, 2000 at 12:00 AM (ET)

What is a pearson correlation and how is it used?":

READERS RESPOND:
(In chronological order. Most recent at the bottom.)

Re: Pearson correlation
Message posted by nancy diehl on March 23, 2000 at 12:00 AM (ET)

If two variables (e.g. an x and a y; like height and weight of an individual)
are related in a way that the paired points, when plotted in a scatterplot,
tend to fall in a straight line, then it is said that there is an association
between the variables and that they are related linearly. A numeric measurement of
the strength of this association between the variables is called the Pearson
Correlation coefficient. Its values range from -1 to +1. If the
value is negative, this indicates there's an inverse relationship between the two
(as one increases, the other decreases). Likewise, if it's positive, then there's a direct
relationship between the two. The closer the correlation value is to -1 or +1, the stronger
the relationship is. If you square this correlation coefficient, r, and multiply it by 100, then
you have something called R-Square, which represents the percentage of variation
going on in y that is being explained by x. The more x can explain or predict
y, the better your correlation.

Your $5 contribution helps cover part the $500 annual cost of keeping this site online.