st: Predicted values where a subgroup of variables are held constant

[Michael Harhay <michael.harhay@gmail.com>]

Dear all,
I want to do a straightforward xb prediction after an OLS regression
on a patient population, but for a subgroup of variables I want to use
the sample mean not the true individual value for the prediction:
I've been playing with both the "predict" and "margins" command but
with no success. Is there an "if" like command I can put after predict
to force this?
After no success trying that I also tried to go about this in a roundabout way:
preserve
foreach var of local varlist `pred' {
   sum `var’, meanonly
   replace `var’ = r(mean)
   }

predict sev5, xb
The predictions are still not adjusted.
Any quick thoughts?
Thanks!

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