From tavery at mun.ca  Mon Nov  1 21:46:53 2004
From: tavery at mun.ca (tavery@mun.ca)
Date: Mon Nov  1 21:46:56 2004
Subject: [Rd] ks.test calculations incorrect (PR#7330)
Message-ID: <20041101204653.C006B11020@slim.kubism.ku.dk>

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.


[Rd] ks.test calculations incorrect (PR#7330)
tavery@mun.ca