Date: Sun, 7 Mar 1999 20:36:49 +0000 (GMT)
From: Prof Brian D Ripley <ripley@stats.ox.ac.uk>
To: Brian Kurotsuchi <bkurotsu@toocool.itslab.calpoly.edu>
Subject: Re: [R] ANOVA f-test
In-Reply-To: <19990307102533.B8181@toocool.itslab.calpoly.edu>
On Sun, 7 Mar 1999, Brian Kurotsuchi wrote:
> I have a rather basic question. How can I get R to generate a ANOVA table
> and a f-value for a hypothesis test such as:
F-value, please. Named after {F}isher, I believe.
> Data: group1 values: 5.2 4.5 6.0 6.1 6.7 5.8
> group2 values: 6.5 8.0 6.1 7.5 5.9 5.6
> ...
>
> H0: mean1 = mean2 = mean3 = mean4
What are these: the means of four groups, two of which are shown?
> HA: at least two means different
>
> where I want to evaluate using a f test statistic?
> F = MSTr/MSE
>
> I'd like a table similar to one that Minitab would produce:
>
> Df Sum Sq Mean Sq F value
> mean1
> mean2
> mean3
> Error
(I don't see MS_Tr in _that_ table.)
Try using aov(response ~ grouping, data=) and its summary method for the
conventional analysis. If you have a four-group one-way layout I have no
idea what the `MINITAB' table means statistically (nor do I recognize it
from my long-ago usage of MINITAB): each mean only has a meaningful line
when you know what else has been fitted, and one should be looking at
contrasts. You can get something like this by mis-using anova.lm.
> Secondly, how can do a second evaluation using a multiple ANOVA compare using
> Tukey's procedure?
Eh? That could mean several things. If you mean Tukey's method of multiple
comparisons, it is not currently available in R. (It is in recent versions
of S-PLUS.) [John Tukey is one of the most prolific of statisticians ever:
"Tukey's procedure" is not at all precise.]
-- Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._