Predict command

[Marthe Dpnt]

dear all,
I use stata 13. When I do "predict r, rstudent", "predict c, cooksd", etc, I have the following message :
"rstudent invalid" r(198) and I do not know how the error comes from

Many thanks in advance for your help

[Clyde Schechter]

What estimation command did you run before -predict-? These options are only valid after -regress-. If you ran them after -logistic- or -xtreg- or something else, the corresponding statistics don't exist.