[Rd] ks.test calculations incorrect (PR#7330)

From: <tavery_at_mun.ca>
Date: Tue 02 Nov 2004 - 07:46:53 EST


Full_Name: t. avery
Version: 2.0.0
OS: windows xp / Linux
Submission from: (NULL) (131.162.134.159)

ks.test does not produce the correct output. If given the script:

d1 <- c(53.63984674,0.383141762,1.915708812,0.383141762,10.72796935,6.896551724,20.30651341,5.747126437,0) d1

d2 <- c(76.43312102,15.2866242,3.821656051,1.27388535,0,0.636942675,1.27388535,0.636942675,0.636942675) d2

ks.test(d1,d2,alternative="two.sided",exact)

The output generates:

        Two-sample Kolmogorov-Smirnov test

data: dd and ddd
D = 0.3333, p-value = 0.6994
alternative hypothesis: two.sided

Warning message:
cannot compute correct p-values with ties in: ks.test(dd, ddd, alternative = "two.sided", exact)

Which is far from the correct D value of:

D = 0.404934475 with a p-value < 0.01

I recommend that noone use this test. I have tested it with various datasets from publications and texts using by-hand calculations.



R-devel@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-devel Received on Tue Nov 02 07:55:40 2004

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