11-07-2016 11:53 AM
I am using SAS 9.4 TS level 1MZ.on window version of 6.1.7601. I went to compare more than two regression lines so anyone could help to do this please? or anyone share this syntax would be highly appreciated.
Thanks in advance!
11-07-2016 12:00 PM
First, which regression procedure are you using? It may helps us to provide some of the code you are running to give us an idea of what may be practical.
Second what kind of comparison are you looking to do? Graphs? Differences of slopes? Differences of Intercepts? Differences of R-squares?
11-07-2016 12:37 PM
11-07-2016 01:37 PM
Here is an example. The slopes are compared as the interaction term between engine size and origin in the ANOVA table, and the predicted values are compared for a 4-liter engine in the LSMeans output :
proc glm data=sashelp.cars; class origin; model horsepower = origin|engineSize; lsmeans origin / at engineSize=4 pdiff; /* At 4-litre engine size */ run;
(for an illustration, look at the ANCOVA graph)