Question

What does a regression analysis tell you?

Answer 1

It reveals the form of relationship between variables.

Explanation:

Please refer to my reply on What is a regression analysis?.

It reveals the form of relationship between variables. For example, whether the relationship is strongly positively related, strongly negatively related or there is no relationship.

For example, rainfall and agriculture productivity are supposed to be strongly correlated but relation is not known. If we identify crop yield to denote agriculture productivity, and consider two variables crop yield `y` and rainfall `x`.

Construction of regression line of `y` on `x` would make sense and would be able to demonstrate the dependence of crop yield on rainfall. We would then be able to estimate crop yield given rainfall with in a limited error. For this we use observed values of rainfall and productivity and try to find a fit that gives us minimum error (deviation from relation arrived at).