In an ANCOVA-like model (using GLM or MIXED or whatever) how do I test whether a Slope=ONE. (not zero, 1)  ... testing whether the estimated slope = 1.   Proc GLM;  Class Group;  Model Y= Group X; ... something like: TEST X=1;   === I know I could look at the CI for the parameter estimates and see if it contains 1; I want a p-value. ??? ... View more