st: overlay

[Berthold Hoppe <berthold.hoppe@charite.de>]

Dear all,

I try to overlay two linear prediction plots using

overlay y x, by(z) function(twoway lfitci).

The linear regressions are made, but before graphing a black screen,  
the error "unrecognized command: sto" r(199) is shown.

Does anyone know, what to do.

Thanks,
Berthold
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