Tukey HSD

Dear R People:

Here is a possible answer to Christophe's problem

   summary(fm1 <- aov(breaks ~ wool + tension, data = warpbreaks))

Df Sum Sq Mean Sq F value   Pr(>F)   
wool         1  450.7   450.7  3.3393 0.073614 . 
tension      2 2034.3  1017.1  7.5367 0.001378 **
Residuals   50 6747.9   135.0                    
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1

     TukeyHSD(fm1, "tension", ordered = TRUE)

Tukey multiple comparisons of means
    95% family-wise confidence level
    factor levels have been ordered

Fit: aov(formula = breaks ~ wool + tension, data = warpbreaks)

$tension
         diff        lwr      upr
M-H  4.722222 -4.6311985 14.07564
L-H 14.722222  5.3688015 24.07564
L-M 10.000000  0.6465793 19.35342

This is from the Example for TukeyHSD.

It gives you the confidence intervals for the level that you set.

Not p values.

Hope this helps!  Sorry to send to the entire list, but deleted original
message.

Sincerely,
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: hodgess at gator.uhd.edu