How to use proc mixed for ANCOVA model

Arthur2 — Tue, 29 Sep 2020 10:59:13 GMT

Hi, I'm using proc mix to fit ANCOVA model to get the following:
1) LS means of each treatment
2) SE of each treatment
3) LS means difference (placebo - each treatment) with placebo as treatn=3
4) SE difference (placebo - each treatment)
5) SD (standard deviation of residuals from the model)
6) Plot studentized residuals versus predicted values, and also check the distribution of (unstandardized) residuals using a plot.

The code is:
ods output lsmeans=estimate
diffs=diff;
proc mixed data = mydata (where=(treatn in (1,2,3)));
by treatn treat avisitn avisit;
class treatn;
model aval = treatn avisitn base;
lsmeans treatn / diff=control('3');
run;
ods output close;

I'm getting error:
"WARNING: Output 'Diff' was not created. Make sure that the output object name, label, or path is spelled correctly. Also, verify
that the appropriate procedure options are used to produce the requested output object. For example, verify that the
NOPRINT option is not used."

Help is needed to resolve the error and guidance to use the proc mix appropriately to achieve above mentioned requirements for ANCOVA.
Thanks

Re: How to use proc mixed for ANCOVA model

ChrisNZ — Thu, 01 Oct 2020 22:57:12 GMT

Moved to STATS forum

Re: How to use proc mixed for ANCOVA model

StatsMan — Fri, 02 Oct 2020 14:54:53 GMT

Duplicate post. Answered in this thread

https://communities.sas.com/t5/Statistical-Procedures/How-to-use-proc-mixed-for-ANCOVA-model/td-p/687455

Re: How to use proc mixed for ANCOVA model

gcjfernandez — Sat, 03 Oct 2020 18:51:12 GMT

I think the problem is in the By statement. Provide more details about the by statement. What happens if you run the code without the By statement?

topic Re: How to use proc mixed for ANCOVA model in Statistical Procedures

How to use proc mixed for ANCOVA model

Re: How to use proc mixed for ANCOVA model

Re: How to use proc mixed for ANCOVA model

Re: How to use proc mixed for ANCOVA model