What is correlation?
Correlation is the degree to which one set of data is linked to another (e.g. height and weight.) Correlation is measured by a correlation coefficient?
How to I read a correlation coefficient?
If the coefficient is between zero and positive one, there is a positive correlation, with +1 being the most reliable correlation.
If the coefficient is between zero and negative one, there is a negative correlation (there is an inverse relationship), with -1 being the most reliable correlation.
A correlation of zero means there is no relationship.
NOTE: Because social events can not be measured as precisely as data collected for the natural sciences, in social sciences, there are seldom correlation coefficients higher than .5 or lower than -.5. However, these correlations are usually considered significant.
How do I measure correlations?