Displaying 20 results from an estimated 6000 matches similar to: "Testing multidimensional random numbers?"
2011 Jul 29
1
How to interpret Kolmogorov-Smirnov stats
Hi,
Interpretation problem ! so what i did is by using the:
>fit1 <- fitdist(vectNorm,"beta")
Warning messages:
1: In dbeta(x, shape1, shape2, log) : NaNs produced
2: In dbeta(x, shape1, shape2, log) : NaNs produced
3: In dbeta(x, shape1, shape2, log) : NaNs produced
4: In dbeta(x, shape1, shape2, log) : NaNs produced
5: In dbeta(x, shape1, shape2, log) : NaNs produced
6: In
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
2006 Sep 23
1
Fitdistr() versus nls()
Hello R-Users,
I'm new to R so I apologize in advance for any big mistake I might
be doing. I'm trying to fit a set of samples with some probabilistic
curve, and I have an important question to ask; in particular I have
some data, from which I calculate manually the CDF, and then I import
them into R and try to fit: I have the x values (my original samples)
and the y values
2008 Feb 28
0
surv2sample 0.1-2
Dear useRs,
There is a new version 0.1-2 of the package surv2sample available on CRAN.
Users of the previous versions should update because a bug in the function
cif2.ks has been fixed.
General information about the package:
surv2sample provides various two-sample tests for right-censored survival
data. Three main areas and corresponding methods are:
* comparison of two survival
2008 Feb 28
0
surv2sample 0.1-2
Dear useRs,
There is a new version 0.1-2 of the package surv2sample available on CRAN.
Users of the previous versions should update because a bug in the function
cif2.ks has been fixed.
General information about the package:
surv2sample provides various two-sample tests for right-censored survival
data. Three main areas and corresponding methods are:
* comparison of two survival
2006 Mar 15
1
(newbie) Weighted qqplot?
Folks,
Normally, in a data frame, one observation counts as one observation
of the distribution. Thus one can easily produce a CDF and (in Splus
atleast) use cdf.compare to compare the CDF (BTW: what is the R
equivalent of the SPlus cdf.compare() function, if any?)
However, if each point should not count equally, how can I weight the
points before comparing the distributions? I was thinking of
2007 May 27
1
Parametric bootstrapped Kolmogorov-Smirnov GoF: what's wrong
Dear R-users,
I want to perform a One-Sample parametric bootstrapped Kolmogorov-Smirnov
GoF test (note package "Matching" provides "ks.boot" which is a 2-sample
non-parametric bootstrapped K-S version).
So I wrote this code:
---[R Code] ---
ks.test.bootnp <- function( x, dist, ..., alternative=c("two.sided", "less",
"greater"), B = 1000 )
{
2006 Dec 04
0
How to calculate area between ECDF and CDF?
Hi all,
I'm working with data to which I'm fitting three-parameter weibull
distributions (shape, scale & shift). The data are of low sample sizes
(between 10 and 80 observations), so I'm reluctant to check my fits
using chi-square (also, I'd like to avoid bin choice issues). I'd use
the Kolmogorov-Smirnov test, but of course this is invalid when the
distribution
2009 Apr 12
1
goodness of fit between two samples of size N (discrete variable)
Hello list:
I generate by simulation (using different procedures) two sample vectors of size N, each corresponding to a discrete variable and I want to text if these samples can be considered as having the same probability distribution (which is unknown). What is the best test for that?
I've read that Kolmogorov-Smirnov and Anderson-Darling tests are restricted to continuous data
2010 Apr 19
2
Truncated Normal Distribution and Truncated Pareto distribution
Dear R helpers,
I have a bimodal dataset dealing with loss amounts. I have divided this dataset into two with the bounds for the first dataset i.e. dataset-A being 5,000$ to 100,000$ and the dataset-B deals with the losses exceeding 100,000$ i.e. dataset-B is left truncated.
I need to fit truncated normal disribution to dataset - I having lower bound of 5000 and upper bound of 100,000. While I
2005 Sep 09
2
test for exponential,lognormal and gammadistribution
hello!
i don't want to test my sample data for normality, but exponential- lognormal-
or gammadistribution.
as i've learnt the anderson-darling-test in R is only for normality and i am
not supposed to use the kolmogorov-smirnov test of R for parameter estimates
from sample data, is that true?
can you help me, how to do this anyway!
thank you very much!
nadja
2007 May 18
0
Anderson-Darling GoF
Hi,
I'm not a statistician so sorry for possible trivial questions ...
I want to perform a GoF test on sample data against several distribution
(like Extreme Value, Phase Type, Pareto, ...).
Since I suspect a long-tailed behaviour on data I want to use
Anderson-Darling (AD) GoF test because it's well known it's more sensible to
tail data.
Looking at R packages the only AD test is
2007 May 18
0
Anderson-Darling GoF (re-sent)
Hi,
I'm not a statistician so sorry for possible trivial questions ...
I want to perform a GoF test on sample data against several distribution
(like Extreme Value, Phase Type, Pareto, ...).
Since I suspect a long-tailed behaviour on data I want to use
Anderson-Darling (AD) GoF test because it's well known it's more
sensible to tail data.
Looking at R packages the only AD test is
2006 Oct 13
0
Comparing of two non-normal distributions
Dear R Users,
Suppose comparing two non-normal distributions is our interest. Like distribution of financial time series, they are negative skewed with fat tail. Which test can better help and in which pachage? ( For example in goodness-of-fit) Kolmogorov-Smirnov test has its own incompatibility. Are there for example Anderson-Darling or Kuiper statistics in R?
I'm grateful to any
2007 Jun 28
0
maximum difference between two ECDF's
Hello,
I have a vector of samples x of length N. Associated with each
sample x_i is a certain weight w_i. All the weights are in another
vector w of the same length N.
I have another vector of samples y of length n (small n). All
these samples have equal weights 1/n. The ECDF of these samples
is defined as for example at
http://en.wikipedia.org/wiki/Empirical_distribution_function and
I can
2004 Jun 17
0
2D Kolmogorov-Smirnov test: solution
Hi - A little while ago I posted a question about the implementation of
a two-dimensional analog of the Kolmogorov-Smirnov test in R[1][2]. As
there isn't one, as far as I know, people might be interested in a very
fast C++ implementation called MUAC which is available as a function
and as a standalone program from
http://www.acooke.org/jara/muac/index.html. Apparently the code is
2000 Mar 01
2
Help please..
Hello R-world,
I am facing a peculiar problem and hope someone out there
can comment on it.
In goodness-of-fit tests for evaluation of distributions,
there are three well-known methods:
1. Chi-square
2. Anderson-Darling
3. Kolmogorov-Sminrov
I am trying to use the second test. Many researchers have
reported results using this test. I wrote programs in C and
now in R to do this. I run into
2007 Mar 03
3
How to convert List object to function arguments?
Dear R gurus,
I have a function "goftests" that receives the following arguments:
* a vector "x" of data values;
* a distribution name "dist";
* the dots list ("...") containing a list a parameters to pass to CDF
function;
and calls several goodness-of-fit tests on the given data values against
the given distribution.
That is:
##### BEGIN CODE SNIP #####
2011 Apr 27
3
Kolmogorov-Smirnov test
Hi,
I have a problem with Kolmogorov-Smirnov test fit. I try fit distribution to
my data. Actualy I create two test:
- # First Kolmogorov-Smirnov Tests fit
- # Second Kolmogorov-Smirnov Tests fit
see below. This two test return difrent result and i don't know which is
properly. Which result is properly? The first test return lower D = 0.0234
and lower p-value = 0.00304. The lower 'D'
2010 Jul 14
2
R's Data Dredging Philosophy for Distribution Fitting
Forum,
I'm a grad student in Civil Eng, took some Stats classes that required
students learn R, and I have since taken to R and use it for as much as I
can. Back in my lab/office, many of my fellow grad students still use
proprietary software at the behest of advisers who are familiar with the
recommended software (Statistica, @Risk (Excel Add-on), etc). I have spent
a lot of time learning