Bookmark and Share

Notice: On April 23, 2014, Statalist moved from an email list to a forum, based at statalist.org.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

st: question: an example of xtmixed: testing differences between groups at specific times


From   "Sun, Wensheng" <wsun@bcm.edu>
To   "statalist@hsphsun2.harvard.edu" <statalist@hsphsun2.harvard.edu>
Subject   st: question: an example of xtmixed: testing differences between groups at specific times
Date   Tue, 8 Jan 2013 19:49:35 -0600

Hi,

I am using –xtmixed- on a longitudinal study with planned measurements at 0, 6, 12 and 24 months, but very few follow-up measurements at the planned time. I have fitted the model and need to evaluate changes from baseline and also differences between two treatment groups at exactly 6, 12 and 24 months. The –xtmixed- followed by –margins- gives margins and standard error at each time. How do I compare them? I am using Stata 12 for Windows. 

An example of that in public shared data should be

. webuse childweight
. xtmixed weight c.age##i.girl || id: age, cov(uns) res(ind) mle variance
. margin girl, at(age=(0.5 1 1.5 2))

What STATA commands should I use if I want to compare the weight between boys and girls at age of 0.5, 1, 1.5, and 2? and How should I compare changes from .5-year to 1 or 1.5 or 2 in girls and boys?

Thank you very much!


Carol
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2018 StataCorp LLC   |   Terms of use   |   Privacy   |   Contact us   |   Site index