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Re: Re: st: How do I run a 3-way repeated ANOVA?


From   "RAMPL Linn" <Linn.RAMPL@insead.edu>
To   <statalist@hsphsun2.harvard.edu>
Subject   Re: Re: st: How do I run a 3-way repeated ANOVA?
Date   Thu, 18 Mar 2010 11:31:12 +0100

"RAMPL Linn" <Linn.RAMPL@insead.edu> wrote:
>I am trying to run a 3-way repeated ANOVA on Stata with Y and X1 X2 X3
>(all X being repeated variables) with SUBJCECT being repeated factor.

Phil wrote:
>Kirk calls this design a randomized block factorial.  Using Stata 11
>notation the model looks like this,

>. anova y x1##x2##x3 subject

************************************************************************
***

When I use this type of notation you suggested to run a 2-way repeated
Anova

anova y x1##x2 subject


                Source |  Partial SS    df       MS           F     Prob
> F
 
------------------+----------------------------------------------------
                 Model |   119976895    87  1379044.77       5.20
0.0000
                        
                    x2 |    20709087     1    20709087      78.10
0.0000
                    x1 |  11012064.4     1  11012064.4      41.53
0.0000
                 x1#x2 |  14525966.3     1  14525966.3      54.78
0.0000
               subject |  73729777.6    84  877735.447       3.31
0.0000
              
              Residual |  66819222.6   252  265155.645   
 
------------------+----------------------------------------------------
                 Total |   186796118   339  551020.997   


I get different results for the F-statistics than using

anova y subject x1 / subject#x1 x2 / subject#x2 x1#x2, repeated(x1 x2)

(this command is taken from
http://www.stata.com/support/faqs/stat/anova2.html "No between-subjects
factors with two repeated variables")


                Source |  Partial SS    df       MS           F     Prob
> F
 
----------------------+-------------------------------------------------
---
                Model  |   167676037   255  657553.085       2.89
0.0000
                       |
               Subject |  73729777.6    84  877735.447       3.01
0.0000
                   x1  |  11012064.4     1  11012064.4      37.77
0.0000
            subject#x1 |  24493569.3    84  291590.111   
 
----------------------+-------------------------------------------------
---
                    x2 |   20709087     1    20709087       74.96
0.0000
            subject#x2 |    23205572    84   276256.81   
 
----------------------+-------------------------------------------------
---
                 x1#x2 |  14525966.3     1  14525966.3      63.82
0.0000
                      
              Residual |  19120081.2    84  227620.015   
 
----------------------+-------------------------------------------------
---
                 Total |   186796118   339  551020.997


(a) Why would this happen (because of the additional interactions?) i.e.
which version is "correct" 
(b) is there another way similar to the 2-way command I described to do
a 
3-way anova?

Thank you for any advice
Best
Linn




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