Many many thanks for the input in this context. Nico
On Thu, Oct 4, 2012 at 4:56 PM, Jose Iparraguirre < jose.iparragui...@ageuk.org.uk> wrote: > Hi, > > You can also have a look at this paper (no subscription needed): > > Herberich, E.; Sikorski, J.; and Hothorn, T. (2010). "A Robust Procedure > for Comparing Multiple Means under Heteroscedasticity in Unbalanced > Designs". PLoSONE, Vol. 5, Issue 3, e9788. doi:10.1371/journal.pone.0009788 > > In this paper, Herberich et al have included a piece of R code to run > their procedure. Their procedure is a modification of Tukey, and as it says > in the title of the paper, it can be used regardless of whether the samples > had different sizes or distributions. > > José > > > José Iparraguirre > Chief Economist > Age UK > > T 020 303 31482 > E jose.iparragui...@ageuk.org.uk > Twitter @jose.iparraguirre@ageuk > > > Tavis House, 1- 6 Tavistock Square > London, WC1H 9NB > www.ageuk.org.uk | ageukblog.org.uk | @ageukcampaigns > > > For a copy of our new Economic Monitor and the full Chief Economist's > report, visit the Age UK Knowledge Hub > http://www.ageuk.org.uk/professional-resources-home/knowledge-hub-evidence-statistics/ > > > For evidence and statistics on the older population, visit the Age UK > Knowledge Hub > http://www.ageuk.org.uk/professional-resources-home/knowledge-hub-evidence-statistics/ > > > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] > On Behalf Of arun > Sent: 04 October 2012 13:59 > To: John Kane > Cc: R help > Subject: Re: [R] t-test > > Hi John, > You are right. With more than two groups, the type 1 error rate should be > a problem. > A.K. > > > > ----- Original Message ----- > From: John Kane <jrkrid...@inbox.com> > To: arun <smartpink...@yahoo.com> > Cc: > Sent: Thursday, October 4, 2012 8:40 AM > Subject: Re: [R] t-test > > My stats are lousy but isnt Nico doing some multiple t-tests when an anova > with some post hoc comparisons complete with a Tukey or Bonferroni > correction looks more suitable? > > Of course I have no idea of the topic area and maybe he has already done > thi. > > John Kane > Kingston ON Canada > > > > -----Original Message----- > > From: smartpink...@yahoo.com > > Sent: Thu, 4 Oct 2012 05:31:55 -0700 (PDT) > > To: nicome...@gmail.com > > Subject: Re: [R] t-test > > > > HI, > > Try this: > > sapply(split(dat,dat$Name),function(x) t.test(x[,2],dat[,2])$p.value) > > # CTK100 CTK103 CTK121 > > #0.86330310 0.32706859 0.02023357 > > A.K. > > > > > > > > ----- Original Message ----- > > From: Nico Met <nicome...@gmail.com> > > To: Rui Barradas <ruipbarra...@sapo.pt> > > Cc: r-help@r-project.org; r-help <r-h...@stat.math.ethz.ch> > > Sent: Thursday, October 4, 2012 6:37 AM > > Subject: Re: [R] t-test > > > > Dear Rui, > > > > Many thanks for help. > > > > "mean for CTK and all" = comparison between mean of all groups ( which > > means second col) vs. each groups like CTK100, CTK121 etc. > > > > Regards > > > > Nico > > > > On Thu, Oct 4, 2012 at 12:28 PM, Rui Barradas <ruipbarra...@sapo.pt> > > wrote: > > > >> Hello, > >> > >> I'm not quite sure I understand, but something like this? > >> > >> tapply(dat$Score, dat$Name, FUN = mean) > >> sapply(unique(dat$Name), function(un){ > > > with(dat, t.test(Score[Name == un], Score[Name != un])$p.value)}) > >> > >> My doubt is in what you mean by "mean for CTK and all". The ?t.test > >> gives > >> a confidence interval for the difference in the means, so maybe you'll > >> have > >> to look there for what you want. > >> > >> Hope this helps, > >> > >> Rui Barradas > >> Em 04-10-2012 10:34, Nico Met escreveu: > >> > >>> Dear Group, > >>> > >>> I want to do a t-test calculation on a large data set. > >>> > >>> I am pasting some part of it > >>> > >>> structure(list(Name = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 3L, > >>> 3L, 3L, 3L, 3L, 3L, 3L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, > >>> 2L), .Label = c("CTK100", "CTK103", "CTK121"), class = "factor"), > > >> Score = c(236.9726, 207.0055, 237.3464, 224.4774, 236.5034, > > >> 206.7382, 233.94, 240.31, 240.9, 235.15, 223.36, 248.67, > > >> 249.25, 201.4051, 244.1689, 182.2756, 229.001, 241.3211, > > >> 196.0453, 232.6055, 225.0783, 196.0453, 232.6055, 225.0783 > > >> )), .Names = c("Name", "Score"), class = "data.frame", row.names > > = > >>> c(NA, > >>> 24L)) > >>> > >>> > >>> I want to compare groups with CTK100 and with all the groups and want > >>> to > >>> save the p-values and mean for each of that particular group (for > >>> example: > >>> mean for CTK and all) > >>> Similarly, for other groups like that CTK121 etc... > >>> > >>> Is there any way to automate this process? > >>> > >>> Thanks for your advice !!!!! > >>> > >>> Nico > >>> > > >> [[alternative HTML version deleted]] > >>> > >>> ______________________________**________________ > >>> R-help@r-project.org mailing list > >>> https://stat.ethz.ch/mailman/**listinfo/r-help< > https://stat.ethz.ch/mailman/listinfo/r-help> > >>> PLEASE do read the posting guide http://www.R-project.org/** > >>> posting-guide.html <http://www.R-project.org/posting-guide.html> > >>> and provide commented, minimal, self-contained, reproducible code. > >>> > >> > >> > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > 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. > > > > > > ______________________________________________ > > R-help@r-project.org mailing list > > 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. > > ____________________________________________________________ > FREE 3D MARINE AQUARIUM SCREENSAVER - Watch dolphins, sharks & orcas on > your desktop! > > > ______________________________________________ > R-help@r-project.org mailing list > 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. > > Age UK and YouthNet are official charities for the Virgin London Marathon > 2013 > > We need you to Run for it. Join the team and help raise vital funds to > bring generations together to combat loneliness and isolation. > > Go to http://www.runforit.org.uk for more information or contact Helen > Parson at helen.pars...@ageuk.org.uk or on 020 303 31369. > > Age UK and YouthNet. A lifeline, online. > > www.runforit.org.uk > > > > Age UK Improving later life > > www.ageuk.org.uk > > > > ------------------------------- > Age UK is a registered charity and company limited by guarantee, > (registered charity number 1128267, registered company number 6825798). > Registered office: Tavis House, 1-6 Tavistock Square, London WC1H 9NA. > > For the purposes of promoting Age UK Insurance, Age UK is an Appointed > Representative of Age UK Enterprises Limited, Age UK is an Introducer > Appointed Representative of JLT Benefit Solutions Limited and Simplyhealth > Access for the purposes of introducing potential annuity and health > cash plans customers respectively. Age UK Enterprises Limited, JLT > Benefit Solutions Limited and Simplyhealth Access are all authorised and > regulated by the Financial Services Authority. > ------------------------------ > > This email and any files transmitted with it are confide...{{dropped:28}} > > ______________________________________________ > R-help@r-project.org mailing list > 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. > [[alternative HTML version deleted]]
______________________________________________ R-help@r-project.org mailing list 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.
