Introduction to Regression: http://goo.gl/WSavsz
 

Linear Regression 1: http://goo.gl/zexJTw
Linear Regression 2: http://goo.gl/pUOOJC

Quadratic Regression 1: http://goo.gl/XjePfn
Quadratic Regression 1:  http://goo.gl/FYlCiE