Thank for your help!! That took care of the problem! Thank you again
David "Kentucky Geologist trying to learn R" Doyle On Sun, Oct 26, 2014 at 12:37 AM, Rolf Turner <r.tur...@auckland.ac.nz> wrote: > On 26/10/14 16:40, David Doyle wrote: > >> Hello, >> >> I'm trying to run kruskal test on some data but the p values seemed way >> too >> low. So I tried it on some similar data and still got p-value = >> 1.611e-09. I'm sure it is a simple mistake but I can't figure it out. >> >> Below is my data and code. Could it be because there are some miss data / >> NAs in the data set?? If so, could some one point me towards a solution?? >> >> Thank you for your time. >> David >> >> mydata <-read.csv("http://doylesdartden.com/R/test.csv", sep=",") >> kruskal.test(mydata, AMMONIA~Well) >> >> Kruskal-Wallis rank sum test >> >> data: mydata >> Kruskal-Wallis chi-squared = 36.3952, df = 1, p-value = 1.611e-09 >> > > Thank you for providing a clear question and an easily reproducible > example. > > The problem is your syntax for the call to the kruskal.test() function. > > It should be: > > kruskal.test(AMMONIA ~ Well, data=mydata) > > This gives a p-value of 1 (which agrees with wilcox.test); t.test() gives > a p-value of 0.7958) so harmony is restored to the universe. > > IMHO there is a bit of a design flaw in kruskal.test(); it should have > thrown an error, given your syntax. The wilcox.test() function *does* > throw an error. > > cheers, > > Rolf Turner > > -- > Rolf Turner > Technical Editor ANZJS > [[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.