KS test and theoretical distribution

x <- runif(100)
y <- runif(100)
ks.test(x,y)
      Two-sample Kolmogorov-Smirnov test

data:  x and y
D = 0.11, p-value = 0.5806
alternative hypothesis: two-sided

ok I expected that, but:

ks.test(runif(100), "runif")
       One-sample Kolmogorov-Smirnov test

data:  runif(100)
D = 0.9106, p-value < 2.2e-16
alternative hypothesis: two-sided

How come?
Pilot error.  The help says

        y: either a numeric vector of data values, or a character string
           naming a cumulative distribution function or an actual
           cumulative distribution function such as ?pnorm?.  Only
           continuous CDFs are valid.

"runif" is not 'an actual cumulative distribution function' ....
--
View this message in context: http://r.789695.n4.nabble.com/KS-test-and-theoretical-distribution-tp3878640p3878640.html
Sent from the R help mailing list archive at Nabble.com.

______________________________________________
R-help at 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.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

KS test and theoretical distribution

Thread (3 messages)