Thank you very much Michael and Bert! I'll have to look for some other statistical test. Have a great holiday!
On Sat, Dec 22, 2018, 10:36 AM Bert Gunter <bgunter.4...@gmail.com wrote: > ... Moreover, you should not analyze proportions in this way, which treats > .5 = 2/4 or .5 = 2000/4000 identically. As David said, you need to work > with a statistician. > > Bert Gunter > > "The trouble with having an open mind is that people keep coming along and > sticking things into it." > -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) > > > On Sat, Dec 22, 2018 at 7:32 AM David L Carlson <dcarl...@tamu.edu> wrote: > >> You may need to spend some more time with the statistician who needs to >> see your data. It is not clear if you have a two sample test or a paired >> sample test. Kruskall-Wallis expects data for each observation, not grouped >> data. Without the observations, the test cannot compute the sample size and >> the degrees of freedom. You have run kruskal.test separately on each >> sample. The kruskal.test is designed for comparing two or more samples. >> >> ---------------------------------------- >> David L Carlson >> Department of Anthropology >> Texas A&M University >> College Station, TX 77843-4352 >> >> -----Original Message----- >> From: R-help <r-help-boun...@r-project.org> On Behalf Of Jenny Liu >> Sent: Saturday, December 22, 2018 7:10 AM >> To: Michael Dewey <li...@dewey.myzen.co.uk> >> Cc: r-help@r-project.org >> Subject: Re: [R] Glitch in Kruskal-Wallis test? >> >> Hi Michael, >> >> Thank you for your reply! I'm testing the difference in proportions. Temp >> is temperature, and Prop is the proportion of insect pupae that survived >> at >> that temperature. I was told by a statistician that the K-W was >> appropriate >> for testing proportions, but perhaps you know of an alternative? I have >> already tested for heteroscedasticity using the Breusch-Pagan test. >> >> Thanks again, >> Jenny >> >> >> >> On Dec 22, 2018 7:38 AM, "Michael Dewey" <li...@dewey.myzen.co.uk> wrote: >> >> Dear Jenny >> >> What exactly do you think you are testing here? You are telling K-W you >> have seven groups each with a single value which is not the usual >> situation for K-W. >> >> Michael >> >> >> On 22/12/2018 04:58, Jenny Liu wrote: >> > Hi everyone, >> > I have been running a K-W test with the attached data, PupMort1. My >> code: >> > kruskal.test(Prop~Temp,data=PupMort1) >> > However, I found that I get the exact same result when I change the >> x-values, as >> > in the attached data PupMort2. >> > Test run with PupMort1Kruskal-Wallis rank sum testdata: Prop by Temp >> >> > Kruskal-Wallis chi-squared = 6, df = 6, p-value = 0.4232 >> > Test run with PupMort2Kruskal-Wallis rank sum testdata: Prop by Temp >> >> > Kruskal-Wallis chi-squared = 6, df = 6, p-value = 0.4232 >> > Does anybody know why this is happening? >> > Thank you! >> > Jenny >> > >> > >> > ______________________________________________ >> > 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. >> > >> >> -- >> Michael >> http://www.dewey.myzen.co.uk/home.html >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> 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. >> >> ______________________________________________ >> 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. >> > [[alternative HTML version deleted]] ______________________________________________ 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.
