Correlation
Unsure about which correlational analysis you should perform? Look here!
How to do a simple Pearson correlation (parametric data):
How to do a simple Spearman correlation (non-parametric data):
How to do a a partial correlation (used for indicating an association between two variables while controlling for the influence of a third variable ):
If you want to find out what the relationship is for categorical data, look at our crosstabs page!