[R] pairwise.t.test for paired data

francogrex francogrex at mail.com
Fri Apr 4 17:20:31 CEST 2008


Dear R-help, I have a question about pairwise.t.test and adjustment for
multiple comparisons for paired data points.
I have the following data:

n=c("x", "x", "x", "x", "x", "x", "x", "x", "x", "x", "y", "y", 
"y", "y", "y", "y", "y", "y", "y", "y", "z", "z", "z", "z", "z", 
"z", "z", "z", "z", "z")

and 

d=c(3.38501220258169, 0.732526675324789, -0.638736410843593,
7.87414894080545, 
3.6341475242877, -2.80762187242111, 14.1405912463741, -9.29904247482419, 
9.8636915453275, 5.43287495347734, 12.2804612051493, 7.83975161028828, 
15.2200332220459, 6.72953902619773, 9.11557944514228, 9.79268012944973, 
7.6112143261283, 10.3912598689021, 8.04934992955112, 13.3935024789408, 
12.1276080143311, 11.2987640203845, 2.05386456839974, 12.8386335687123, 
3.84418682233211, 17.4626505871045, 6.5947625121599, -10.6664750811034, 
21.3346023277454, 4.99216977422232)

Then I do the tests

> pairwise.t.test(d,n,p.adjust="bonf",paired=F)

        Pairwise comparisons using t tests with pooled SD 

data:  d and n 

  x     y    
y 0.092 -    
z 0.326 1.000

P value adjustment method: bonferroni

Assuming the data are paired:

> pairwise.t.test(d,n,p.adjust="bonf",paired=T)

        Pairwise comparisons using t tests with pooled SD 

data:  d and n 

  x     y    
y 0.092 -    
z 0.326 1.000

P value adjustment method: bonferroni 

I have no indication that the test is taking into account that the data are
paired! Is it possible to do a pairwise t test with adjustement for multiple
comparisons using pairwise.t.test? If not any other function for that?
Thanks.

-- 
View this message in context: http://www.nabble.com/pairwise.t.test-for-paired-data-tp16491877p16491877.html
Sent from the R help mailing list archive at Nabble.com.



More information about the R-help mailing list