On 10 Feb 2015, at 11:45 , Thomas Chesney <thomas.ches...@nottingham.ac.uk> wrote:
> I'm using pairwise.t.test() with 6 groups, but the dataset the 6 groups are > in actually contains 24 groups. > > When I run the test with all 24 groups the results I'm getting between Group > 1 and Group 2 are very different from the results I'm getting between Group 1 > and Group 2 when I split off the 6 groups and run the test. When only 6 > groups are included the results are highly significant but with all 24 groups > the results are insignificant. > > I'm not adjusting p.values. The code I'm running is: > > res <- pairwise.t.test(dat$Adopt, dat$Group, p.adj="none") > > I thought the above code would run exactly the same test on Groups 1 and 2, > regardless of how many groups are in the dataset. Can anyone explain what's > going on? Check out pool.sd on the help page. -pd > > Thank you, > > Thomas Chesney > > > > > This message and any attachment are intended solely for the addressee > and may contain confidential information. If you have received this > message in error, please send it back to me, and immediately delete it. > > Please do not use, copy or disclose the information contained in this > message or in any attachment. Any views or opinions expressed by the > author of this email do not necessarily reflect the views of the > University of Nottingham. > > This message has been checked for viruses but the contents of an > attachment may still contain software viruses which could damage your > computer system, you are advised to perform your own checks. Email > communications with the University of Nottingham may be monitored as > permitted by UK legislation. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. -- Peter Dalgaard, Professor, Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
