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Re: st: Anova and pwcompare and not estimable
From
Martyn Sherriff <[email protected]>
To
[email protected]
Subject
Re: st: Anova and pwcompare and not estimable
Date
Tue, 10 Jan 2012 10:04:13 +0000
I agree, it does look a little odd. I cannot think of an explanation
at the moment. Sorry.
Martyn
On 9 January 2012 22:04, Garry Anderson <[email protected]> wrote:
> Dear Statalist and Martyn,
>
> Thank you for referring me to the excellent discussion.
>
> I have used -pwcompare calib#shape, asbalanced emptycells(reweight)- and obtained the following.
>
> I would have expected two different standard errors for the two types of comparison (within calib, and between calib). The -anova- defines which error term to use for each factor and I would have thought this carries over to comparisons of means.
>
>
> set more of
> use http://www.stata-press.com/data/r12/t77
> gen sub1to6 = subject
> replace sub1to6=sub1to6 + 3 if calib==2
> anova score calib / sub1to6|calib shape calib#shape,repeated(shape)
>
> pwcompare calib#shape, asbalanced emptycells(reweight)
>
> Pairwise comparisons of marginal linear predictions
>
> Margins : asbalanced
> Empty cells : reweight
>
> -----------------------------------------------------------------
> | Unadjusted
> | Contrast Std. Err. [95% Conf. Interval]
> ----------------+------------------------------------------------
> calib#shape |
> (1 2) vs (1 1) | -1 .9077853 -2.977894 .9778942
> (1 3) vs (1 1) | 3 .9077853 1.022106 4.977894
> (1 4) vs (1 1) | .6666667 .9077853 -1.311227 2.644561
> (2 1) vs (1 1) | 3 .9077853 1.022106 4.977894
> (2 2) vs (1 1) | 1.333333 .9077853 -.6445608 3.311227
> (2 3) vs (1 1) | 4.666667 .9077853 2.688773 6.644561
> (2 4) vs (1 1) | 5.333333 .9077853 3.355439 7.311227
> (1 3) vs (1 2) | 4 .9077853 2.022106 5.977894
> (1 4) vs (1 2) | 1.666667 .9077853 -.3112275 3.644561
> (2 1) vs (1 2) | 4 .9077853 2.022106 5.977894
> (2 2) vs (1 2) | 2.333333 .9077853 .3554392 4.311227
> (2 3) vs (1 2) | 5.666667 .9077853 3.688773 7.644561
> (2 4) vs (1 2) | 6.333333 .9077853 4.355439 8.311227
> (1 4) vs (1 3) | -2.333333 .9077853 -4.311227 -.3554392
> (2 1) vs (1 3) | 2.66e-15 .9077853 -1.977894 1.977894
> (2 2) vs (1 3) | -1.666667 .9077853 -3.644561 .3112275
> (2 3) vs (1 3) | 1.666667 .9077853 -.3112275 3.644561
> (2 4) vs (1 3) | 2.333333 .9077853 .3554392 4.311227
> (2 1) vs (1 4) | 2.333333 .9077853 .3554392 4.311227
> (2 2) vs (1 4) | .6666667 .9077853 -1.311227 2.644561
> (2 3) vs (1 4) | 4 .9077853 2.022106 5.977894
> (2 4) vs (1 4) | 4.666667 .9077853 2.688773 6.644561
> (2 2) vs (2 1) | -1.666667 .9077853 -3.644561 .3112275
> (2 3) vs (2 1) | 1.666667 .9077853 -.3112275 3.644561
> (2 4) vs (2 1) | 2.333333 .9077853 .3554392 4.311227
> (2 3) vs (2 2) | 3.333333 .9077853 1.355439 5.311227
> (2 4) vs (2 2) | 4 .9077853 2.022106 5.977894
> (2 4) vs (2 3) | .6666667 .9077853 -1.311227 2.644561
> -----------------------------------------------------------------
>
> .
>
> Kind regards, Garry
>
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf Of Martyn Sherriff
> Sent: Monday, 9 January 2012 10:08 PM
> To: [email protected]
> Subject: Re: st: Anova and pwcompare and not estimable
>
> pwcompare calib#shape, asbalanced emptycells(reweight)
>
> There is an excellent discussion of this at http://www.ats.ucla.edu/stat/stata/faq/margins_nested1.htm
>
> Cheers,
> Martyn
>
> On 9 January 2012 08:52, Garry Anderson <[email protected]> wrote:
>> pwcompare calib#shape
> *
> * 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/
*
* 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/