On Mar 13, 2010, at 2:34 PM, Tal Galili wrote:

Hello all,

A friend just showed me how ks.test fails to work with pbinom for small
"size".
Example:

x<-rbinom(10000,10,0.5)
x2<-rbinom(10000,10,0.5)
ks.test(x,pbinom,10,0.5)
ks.test(x,pbinom,size = 10, prob= 0.5)
ks.test(x,x2)


The tests gives significant p values, while the x did come from
binom  with size = 10 prob = 0.5.

The first sentence of Details in the ks.test help page:
"If y is numeric, a two-sample test of the null hypothesis that x and y were drawn from the same _continuous_ distribution is performed." (_continuous_ in italics.)

This has come up in r-help so frequently that I nominate it for addition to the FAQ. Searching with RSiteSearch() on "ks.test" with "ties" or "continuous" should bring up useful commentary from experts.

--
David.

What test should I use instead ?


Thanks,
Tal


        [[alternative HTML version deleted]]


David Winsemius, MD
West Hartford, CT

______________________________________________
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.

Reply via email to