R help - Jun 2014 - aov + pairwise.t.test: only selected pairs

Hi,

I have a 1-way anova result and want to do a post test.

I want to do pairwise t-tests where the global variance is taken into
account (i.e. a real post test on the anova result, not multiple simple t
tests on the samples).

I understand I should use pairwise.t.test() for that. However, it does not
allow me to select specific pairs, it always analyzes all pairs. How can I
analyze specific pairs only?

Thanks
Andreas

	[[alternative HTML version deleted]]

Have a look at the multcomp package. The examples in glht() demonstrate how to
specify the required contrasts.

Best regards,

ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek / Research Institute for Nature and
Forest
team Biometrie & Kwaliteitszorg / team Biometrics & Quality Assurance
Kliniekstraat 25
1070 Anderlecht
Belgium
+ 32 2 525 02 51
+ 32 54 43 61 85
Thierry.Onkelinx at inbo.be
www.inbo.be

To call in the statistician after the experiment is done may be no more than
asking him to perform a post-mortem examination: he may be able to say what the
experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not ensure
that a reasonable answer can be extracted from a given body of data.
~ John Tukey


-----Oorspronkelijk bericht-----
Van: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
Namens Andreas Maunz
Verzonden: woensdag 11 juni 2014 10:02
Aan: r-help at r-project.org
Onderwerp: [R] aov + pairwise.t.test: only selected pairs

Hi,

I have a 1-way anova result and want to do a post test.

I want to do pairwise t-tests where the global variance is taken into account
(i.e. a real post test on the anova result, not multiple simple t tests on the
samples).

I understand I should use pairwise.t.test() for that. However, it does not allow
me to select specific pairs, it always analyzes all pairs. How can I analyze
specific pairs only?

Thanks
Andreas

        [[alternative HTML version deleted]]

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