Hi all -      I have run a linear regression on my students' test score data and the r-squared value is high and p-value is low which would be great - except my residuals plot showed a different story. The residual plots did not show uniform randomness, my data appeared to be curved/not-linear. My residuals histogram is skewed a bit to the right.   Seems as though I need to transform a variable or create a nonlinear model. But I need help with SAS on how to do this. Some random, sample data is attached here that shows the types of data i'm using. I am using the following variables:   Dependent Variable: Mean Test Score Independent Variable: % Free and Reduced Lunch   & I am separating my analyses by test subject (literacy or math).   I have NO idea how to run a procedure in SAS to help me build a nonlinear model. Is anyone able to assist me or point me in the right direction?   I tried PROC NLIN, but get lost with the parameters...     ... View more