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

tavery at mun.ca tavery at mun.ca
Mon Nov 1 21:46:53 CET 2004

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

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)

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


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.

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