Re: st: AW: AW: Plotting 3 way continuous interactions in regression

[Kris Anderson <andersok@reed.edu>]

Unfortunately, the _SAP was not the problem. It was an artifact of my 
cut and paste.

The message I receive is after the lincom $HPNHAF /* slope 1*/ command 
It says SAP/ invalid name.

I am sorry but I don't follow the code below. What is this doing? I am 
relatively new to coding in Stata.

Martin Weiss wrote:
> <> 
>
> Apart from the problem mentioned before, your strategy is technically a
> little cumbersome but valid...
>
>
> *************
> sysuse auto, clear
> reg pr we len he
>
> su he, mean
> gl headmean=r(mean)
>
> gl mycovariates /* 
>  */ "weight*($headmean)+2*le"
>
> lincom $mycovariates
> global b1 = r(estimate)
>
> di $b1
> *************
>
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Martin Weiss
> Gesendet: Donnerstag, 13. August 2009 14:06
> An: statalist@hsphsun2.harvard.edu
> Betreff: st: AW: Plotting 3 way continuous interactions in regression
>
>
> <> 
>
> You use "_SAP" in your -regress- command, but "SAP" in your -global-s....
>
> What exactly does Stata say after which command?
>
>
>
> HTH
> Martin
>
>
> -----Ursprüngliche Nachricht-----
> Von: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Im Auftrag von Kris Anderson
> Gesendet: Donnerstag, 13. August 2009 01:54
> An: statalist@hsphsun2.harvard.edu
> Betreff: st: Plotting 3 way continuous interactions in regression
>
> Hi,
>
> I am stuck on a piece of code that I can't seem to debug. I am trying to 
> plot a 3-way interaction using the FAQ on plotting these interactions 
> with covariates. The code hangs up as I try to compute 4 simple slopes. 
> The program tells me the name of my interaction term is invalid. Can 
> anyone see a problem here? I tried renaming the variable but it didn't help.
>
> Thanks
>
> regress avgdrink age sex gradedich white hisp csocanx caffil cpn SAF SP 
> AP _SAP if currentdrinker > 0
>
> sum csocanx
> global hi=r(max)
> global lo=r(min)
> sum caffil
> global HAF=r(mean)+r(sd)
> global LAF=r(mean)-r(sd)
> sum cpn
> global HPN=r(mean) +r(sd)
> global LPN=r(mean) -r(sd)
> sum age
> global mage=r(mean)
> sum gradedich
> global mgrade=r(mean)
> sum white
> global mwhite=r(mean)
> sum hisp
> global mhisp=r(mean)
> global HPNHAF "csocanx + ($HPN)*SP + ($HAF)*SAF + ($HPN)*($HAF)*SAP"
> global HPNLAF "csocanx + ($HPN)*SP + ($LAF)*SAF + ($HPN)*($LAF)*SAP"
> global LPNHAF "csocanx + ($LPN)*SP + ($HAF)*SAF + ($LPN)*($HAF)*SAP"
> global LPNLAF "csocanx + ($LPN)*SP + ($LAF)*SAF + ($LPN)*($LAF)*SAP"
> lincom $HPNHAF /* slope 1*/
> global b1 = r(estimate)
> lincom $HPNLAF /* slope 2*/
> global b2 = r(estimate)
> lincom $LPNHAF /* slope 3*/
> global b3 = r(estimate)
> lincom $LPNLAF /* slope 4*/
> global b4 = r(estimate)
>
>
>
>
>
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--
Kristen G. Anderson, Ph.D.
Assistant Professor of Psychology, Reed College
Principal Investigator, Adolescent Health Research Program
Licensed Clinical Psychologist (OR)
3203 SE Woodstock Blvd., Portland, OR 97202
Phone: 503-517-7410
Fax: 503-517-7610
http://academic.reed.edu/psychology/ahrp/
*
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