I am struggling with this seemly simple ANOVA, but I
can't get it set correctly. I have 40 students
randomly allocated to 4 experimental stress groups.
The diastolic blood pressure was measured for each
student at baseline and at five additional times. The
lay out is something like this:
. table time group
----------------------------------
| group
time | 0 1 2 3
----------+-----------------------
0 | 10 10 10 10
1 | 10 10 10 10
2 | 10 10 10 10
3 | 10 10 10 10
4 | 10 10 10 10
5 | 10 10 10 10
----------------------------------
Note that there are 10 students in each -group-, but
each student was measured at 6 different times. Could
someone please tell me what is the correct Stata
command for this repeated ANOVA?
This is a simple split plot design that shows up everywhere in
biology. You've got one between-subjects factor (group), and one
within-subjects factor (time). You can analyze this design using a
number of Stata commands: anova, manova, or xtmixed. Take a look at
the UCLA page which covers classical designs using ANOVA and the
equivalent xtmixed command: