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. anova m id  method, repeat( method)
<Top of output suppressed>
â?¦
Between-subjects error term:  id
                     Levels:  23        (22 df)
     Lowest b.s.e. variable:  id

Repeated variable: method
                                          Huynh-Feldt epsilon        =  0.6357
                                          Greenhouse-Geisser epsilon =  0.6174
                                          Box's conservative epsilon =  0.5000

                                            ------------ Prob > F ------------
                  Source |     df      F    Regular    H-F      G-G      Box
              -----------+----------------------------------------------------
                  method |      2    10.12   0.0002   0.0020   0.0022   0.0043
                Residual |     44
              ----------------------------------------------------------------

MANOVA reports a p-value of 2.519e-07, whereas the Huynh-Feldt p-value from ANOVA is 0.0022.
Any idea why they are so different? Am I doing something wrong? 

Thank you,
Ricardo

Data:
      id     m1     m2     m3
     106   22.2   30.6   13.9
     111   26.4   32.2   14.6
     119   23.6   28.9   26.7
     122   27.4   38.0   28.9
     130   17.5   24.5   41.4
     131   18.4   21.5   20.2
     133   28.1   28.1   22.3
     135   33.5   38.5   29.9
     140   18.9   25.7   15.1
     144   21.2   28.3   37.0
     149   18.8   25.6   15.5
     152   22.4   31.5   28.5
     153   21.5   28.6   22.5
     158   27.9   37.6   37.2
     167   30.1   42.3   24.0
     168   28.5   36.9   32.4
     171   23.5   36.7   27.8
     176   24.6   24.5   25.8
     180   29.4   30.3   15.2
     188   23.2   24.6    9.1
     191   25.7   31.7   31.2
     192   20.1   19.7    8.2
     194   23.4   27.7    6.0



Ricardo Ovaldia, MS
Statistician 
Oklahoma City, OK


--- On Wed, 2/1/12, Ricardo Ovaldia <ovaldia@yahoo.com> wrote:

> From: Ricardo Ovaldia <ovaldia@yahoo.com>
> Subject: Re: st: repeated measures ANOVA to MANOVA
> To: statalist@hsphsun2.harvard.edu
> Date: Wednesday, February 1, 2012, 9:18 AM
> Never mind. Thank you. I found the
> answer on page 359 of the manual.
> I am now concerned because the pvalue from MANOVA is so much
> smaller than the Huynh-Feldt corrected p-value
> 
> Thank you again,
> Ricardo
> 
> Ricardo Ovaldia, MS
> Statistician 
> Oklahoma City, OK
> 
> 
> --- On Wed, 2/1/12, Ricardo Ovaldia <ovaldia@yahoo.com>
> wrote:
> 
> > From: Ricardo Ovaldia <ovaldia@yahoo.com>
> > Subject: st: repeated measures ANOVA to MANOVA
> > To: "Statalist" <statalist@hsphsun2.harvard.edu>
> > Date: Wednesday, February 1, 2012, 8:50 AM
> > I have data on 23 patients that were
> > evaluated using three competing medical methods. I
> used
> > repeated measures ANOVA and reported the Huynh-Feldt
> > corrected p-value. A reviewer suggested that it would
> be
> > better to do a MANOVA. However, when I try this, 
> Stata
> > reports the error:
> > 
> > . manova m1 m2 m3=id
> > matrix not positive definite
> > insufficient residual degrees of freedom for this
> > multivariate model
> > 
> > Any help will be appreciated.
> > Ricardo
> > 
> > Here is the data:
> > . cl id m1 m2 m3
> > 
> >            id 
> >    m1     m2 
> >    m3
> >   1.     
> > 106   22.2   30.6   13.9
> >   2.     
> > 111   26.4   32.2   14.6
> >   3.     
> > 119   23.6   28.9   26.7
> >   4.     
> > 122   27.4   38.0   28.9
> >   5.     
> > 130   17.5   24.5   41.4
> >   6.     
> > 131   18.4   21.5   20.2
> >   7.     
> > 133   28.1   28.1   22.3
> >   8.     
> > 135   33.5   38.5   29.9
> >   9.     
> > 140   18.9   25.7   15.1
> >  10.     
> > 144   21.2   28.3   37.0
> >  11.     
> > 149   18.8   25.6   15.5
> >  12.     
> > 152   22.4   31.5   28.5
> >  13.     
> > 153   21.5   28.6   22.5
> >  14.     
> > 158   27.9   37.6   37.2
> >  15.     
> > 167   30.1   42.3   24.0
> >  16.     
> > 168   28.5   36.9   32.4
> >  17.     
> > 171   23.5   36.7   27.8
> >  18.     
> > 176   24.6   24.5   25.8
> >  19.     
> > 180   29.4   30.3   15.2
> >  20.     
> > 188   23.2   24.6   
> > 9.1
> >  21.     
> > 191   25.7   31.7   31.2
> >  22.     
> > 192   20.1   19.7   
> > 8.2
> >  23.     
> > 194   23.4   27.7   
> > 6.0
> > 
> > 
> > Ricardo Ovaldia, MS
> > Statistician 
> > Oklahoma City, OK
> > *
> > *   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/
> > 
> 
> *
> *   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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