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Re: st: Re: XTMixed / Repeated Measures


From   Paul Bransom <[email protected]>
To   [email protected]
Subject   Re: st: Re: XTMixed / Repeated Measures
Date   Sat, 3 Jan 2009 02:44:27 -0800 (PST)

George,
I am afraid I had to prepare the contrast matrix "manually" (There has been some earlier discussion on the list about limitations in the way Stata handles contrasts).

anova y a s, repeated(a)

Get the design matrix
test, showorder

 Order of columns in the design matrix
      1: _cons
      2: (a==1)
      3: (a==2)
      4: (a==3)
      5: (a==4)
      6: (s==1)
      7: (s==2)
      8: (s==3)
      9: (s==4)
     10: (s==5)
     11: (s==6)
     12: (s==7)
     13: (s==8)

Enter the contrast matrix (I tend to run it as a do file)
matrix input m1 = (0,1,-1,0,0,0,0,0,0,0,0,0,0  \  ///
0,1,0,-1,0,0,0,0,0,0,0,0,0  \ ///
0,1,0,0,-1,0,0,0,0,0,0,0,0 \ ///
0,0,1,-1,0,0,0,0,0,0,0,0,0 \ ///
0,0,1,0,-1,0,0,0,0,0,0,0,0 \ ///
0,0,0,1,-1,0,0,0,0,0,0,0,0)

Test the contrast
. test, test(m1) mtest(sidak)

 ( 1)  a[1] - a[2] = 0
 ( 2)  a[1] - a[3] = 0
 ( 3)  a[1] - a[4] = 0
 ( 4)  a[2] - a[3] = 0
 ( 5)  a[2] - a[4] = 0
 ( 6)  a[3] - a[4] = 0
       Constraint 3 dropped
       Constraint 4 dropped
       Constraint 5 dropped

---------------------------------------
       |    F(df,21)     df       p
-------+-------------------------------
  (1)  |        0.71      1     0.9571 #
  (2)  |        4.45      1     0.2513 #
  (3)  |       30.08      1     0.0001 #
  (4)  |        1.60      1     0.7740 #
  (5)  |       21.53      1     0.0008 #
  (6)  |       11.39      1     0.0170 #
-------+-------------------------------
  all  |       11.63      3     0.0001
---------------------------------------
              # Sidak adjusted p-values

Paul




--- On Fri, 2/1/09, George Hoffman <[email protected]> wrote:

> From: George Hoffman <[email protected]>
> Subject: Re: st: Re: XTMixed / Repeated Measures
> To: [email protected]
> Date: Friday, 2 January, 2009, 7:46 PM
> Paul - how do you get the matrix to mtest following anova?
> Thanks
> George Hoffman
> 
> 
> > From: Paul Bransom <[email protected]>
> > Reply-To: <[email protected]>
> > Date: Fri, 2 Jan 2009 04:43:15 -0800
> > To: <[email protected]>
> > Subject: Re: st: Re: XTMixed / Repeated Measures
> > 
> > :
> 
> *
> *   For searches and help try:
> *   http://www.stata.com/help.cgi?search
> *   http://www.stata.com/support/statalist/faq
> *   http://www.ats.ucla.edu/stat/stata/


      

*
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