# Re: st: repeated measures MANOVA with continous covariate

 From khigbee@stata.com To statalist@hsphsun2.harvard.edu Subject Re: st: repeated measures MANOVA with continous covariate Date Thu, 11 Mar 2004 11:21:55 -0600

```Jim.Seward@sunhealth.org asks:

> I have some data which consists of memory test scores which were repeated
> on a sample 5 times.  I am interested in seeing if the mean scores for the
> tests change over time.  Following the instructions in the Stata FAQ: "How
> can I do multivariate repeated measures in Stata" I did a repeated measures
> MANOVA.
>
> Now I want to see if age is an influence.  The FAQ describes how to do
> repeated measures MANOVA with a between-subjects factor with 2 levels.
> Will this procedure work with age, a continuous variable?

The MANOVA FAQ mentioned above is provided by the UCLA Academic
Technology Services group.  The FAQ is at

http://www.ats.ucla.edu/stat/stata/faq/manovarep.htm

and Jim probably got there by first typing -search manova- or
something similar in Stata and then clicking on one of the links
provided.  (By the way, much thanks to Michael Mitchell and all
the rest at UCLA ATS for this FAQ and so many wonderful Stata
resources on their website.)

You can also find various examples in the manual entry
"[R] manova" (version 8 of Stata).  Examples of repeated measures
MANOVA start on page 395 of the manual.

Following those examples in the manual is an example of using a
continuous covariate (starting on page 407).

Following along with a similar thing as given in the FAQ, you
can say

manova y1 y2 y3 y4 = x , continuous(x)
mat ymat = (1,0,0,-1\0,1,0,-1\0,0,1,-1)
manovatest x, ytransform(ymat)

where x is your continuous variable.

Ken Higbee    khigbee@stata.com
StataCorp     1-800-STATAPC

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```