Displaying 20 results from an estimated 2000 matches similar to: "ks.test calculations incorrect (PR#7330)"
2011 Oct 06
2
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
2006 Feb 03
2
Problems with ks.test
Hi everybody,
while performing ks.test for a standard exponential distribution on samples
of dimension 2500, generated everytime as new, i had this strange behaviour:
>data<-rexp(2500,0.4)
>ks.test(data,"pexp",0.4)
One-sample Kolmogorov-Smirnov test
data: data
D = 0.0147, p-value = 0.6549
alternative hypothesis: two.sided
>data<-rexp(2500,0.4)
2001 Jul 01
0
ks.test doesn't compute correct empirical distribution if there are ties in the data (PR#1007)
Full_Name: Andrew Grant McDowell
Version: R 1.1.1 (but source in 1.3.0 looks fishy as well)
OS: Windows 2K Professional (Consumer)
Submission from: (NULL) (194.222.243.209)
In article <xeQ_6.1949$xd.353840@typhoon.snet.net>,
johnt@tman.dnsalias.com writes
>Can someone help? In R, I am generating a vector of 1000 samples from
>Bin (1000, 0.25). I then do a Kolmogorov Smirnov test
2005 Oct 02
1
rate instead of scale in ?ks.test
I am not sure whether I'm doing something wrong or there is a bug in the
documentation of ks.test. Following the posting guide, as I'm not sure,
I haven't found this in the bug tracker, and the R FAQ says that stats
is an Add-on package of R, I think this is the place to send it.
?ks.test provides the example
<QUOTE>
# Does x come from a shifted gamma distribution with shape 3
2001 Jul 01
1
(PR#1007) ks.test doesn't compute correct empirical
On Sun, 1 Jul 2001 mcdowella@mcdowella.demon.co.uk wrote:
> Full_Name: Andrew Grant McDowell
> Version: R 1.1.1 (but source in 1.3.0 looks fishy as well)
> OS: Windows 2K Professional (Consumer)
> Submission from: (NULL) (194.222.243.209)
Please upgrade: we've found a number of Win2k bugs and worked around them
since then, let alone teh bug fixes and improvements in R ....
>
2008 Mar 08
1
ks.test troubles
Hi there!
I have two little different data. One is a computer test on people, the
other is a paper and pencil test. two boxplots show me that the data is
almost the same.
So now I'd like to know if I could handle all data as one, by testing
with ks.test:
====
> ks.test(el$angststoer, fl$angststoer)
Two-sample Kolmogorov-Smirnov test
data: el$angststoer and fl$angststoer
D =
2009 Jul 22
0
ks.test - The two-sample two-sided Kolmogorov-Smirnov test with ties (PR#13848)
Full_Name: Thomas Waterhouse
Version: 2.9.1
OS: OS X 10.5.7
Submission from: (NULL) (216.239.45.4)
ks.test uses a biased approximation to the p-value in the case of the two-sample
test with ties in the pooled data. This has been justified in R in the past by
the argument that the KS test assumes a continuous distribution. But the
two-sample test can be extended to arbitrary distributions by a
2001 Oct 26
1
ks.test (PR#1004)
The note to 1004 says "fixed for 1.3.1"
Uh. No. It ain't.
The problem was more serious than guessed as even the simplest testing
would show.
For example, Example 5.4 in Hollander and Wolfe (Nonparametric Statistical,
Methods, 2nd ed., Wiley, 1999, pp. 180-181)
R Version 1.3.1 (SuSE Linux 7.1)
> X <-
2005 Mar 18
1
Pb with ks.test pvalue
Hello,
While doing test of normality under R and SAS, in order to prove the efficiency of R to my company, I notice
that Anderson Darling, Cramer Van Mises and Shapiro-Wilk tests results are quite the same under the two environnements,
but the Kolmogorov-smirnov p-value really is different.
Here is what I do:
> ks.test(w,pnorm,mean(w),sd(w))
One-sample Kolmogorov-Smirnov test
data: w
D
2010 Aug 20
3
how to interpret KS test
Dear R users
I am using KS test to compare two different distribution for the same
variable (temperature) for two different time periods.
H0: the two distributions are equal
H1: the two distributions are different
ks.test (temp12, temp22)
Two-sample Kolmogorov-Smirnov test
data: temp12 and temp22
D = 0.2047, p-value < 2.2e-16
alternative hypothesis: two-sided
Warning message:
In
2001 Jun 29
1
KS test in R.1.3.0 has incorrect p-values. (PR#1004)
Based on a report to the Windows maintainers from Richard Rowe
<Richard.Rowe@jcu.edu.au>:
NEWS for 1.3.0 says
o Exact p-values are available for the two-sided two-sample
Kolmogorov-Smirnov test.
I think the (new) p-values are computed but are backwards:
> set.seed(123)
> x <- rnorm(50)
> y <- runif(50)
> ks.test(x,y, exact=T)$p
[1] 1
> 1 - ks.test(x,y,
2006 Jul 09
1
KS Test Warning Message
All,
Happy World Cup and Wimbledon. This morning finds me with the first
of my many daily questions.
I am running a ks.test on residuals obtained from a regression model.
I use this code:
> ks.test(Year5.lm$residuals,pnorm)
and obtain this output
One-sample Kolmogorov-Smirnov test
data: Year5.lm$residuals
D = 0.7196, p-value < 2.2e-16
alternative hypothesis: two.sided
Warning
2002 Mar 26
3
ks.test - continuous vs discrete
I frequently want to test for differences between animal size frequency
distributions. The obvious test (I think) to use is the Kolmogorov-Smirnov
two sample test (provided in R as the function ks.test in package ctest).
The KS test is for continuous variables and this obviously includes length,
weight etc. However, limitations in measuring (e.g length to the nearest
cm/mm, weight to the nearest
2001 Nov 09
2
ks.test
Dear R-List members,
I want to check if a set of measurements follows better a
gamma or a lognormal distribution (see data below).
Using shapiro.test I can test for normality (shapiro.test(log
(Lt)).
To test for gamma (and normal) distribution I would use
ks.test but I need to specify its shape and scale. How should
I calculate these values in R?
I tried
> Lt.fit <- glm(Lt ~ 1,
2000 Apr 27
0
What is ks.test saying?
Hello!
I have two matrices of equal dimension ll and lu that I want to do a
ks.test on corresponding rows in these matrices (dim(ll) is [1] 101 100).
If I do e.g. > ks.test(ll[50,],lu[50,])
just for testing, it displays a lot of numbers, and some more info:
[116] -3.000000e-02 -4.000000e-02 -4.000000e-02 -3.000000e-02 -4.000000e-02
[121] -3.000000e-02 -4.000000e-02 -3.000000e-02 -2.000000e-02
1999 Apr 09
2
KS test from ctest package
This question is mainly aimed at Kurt Hornik as author of the ctest package,
but I'm cc'ing it to r-help as I suspect there will be other valuable
opinions out there.
I have been attempting 2 sample Kolmogorov-Smirnov tests using the ks.test
function from the ctest package (ctest v.0.9-15, R v.0.63.3 win32). I am
comparing fish length-frequency distributions. My main reference for the
2007 Nov 16
2
ks.test
Hello,
I want to do normality test on my data
I write this but I don't understand the display of the results
ks.test(data,"pnorm")
In fact I want to know if my data is a normal distribution. I have to check the p-value or D?
Thanks.
_____________________________________________________________________________
l
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2010 Aug 04
4
KS Test question (2)
Hi R Users,
I have two vectors, x and y, of equal length representing two types of
data from two studies. I would like to test if they are similar enough
to use them interchangeably. No assumptions about distributions can be
made (initial tests clearly show that they are not normal).
Here some result:
Two-sample Kolmogorov-Smirnov test
data: x and y
D = 0.1091, p-value < 2.2e-16
alternative
2001 Jul 03
0
(PR#1007) ks.test doesn't compute correct empirical distribution if there are ties in the data
In message <Pine.GSO.4.31.0107010731110.7616-100000@auk.stats>, Prof
Brian D Ripley <ripley@stats.ox.ac.uk> writes
>
>You do realize that the Kolmogorov tests (and the Kolmogorov-Smirnov
>extension) assume continuous distributions, so the distribution theory
>is not valid in this case?
>
>S-PLUS does stop you doing this:
>
>> ks.gof(o,
2011 Oct 13
1
KS test
Hi!
how can I do the Kolmogorov Smirnov test for discrepancy between the
estimated and empirical tails?
Regards
Anuradha
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