Displaying 20 results from an estimated 2000 matches similar to: "multivariate Shapiro Wilks test"
2005 Aug 03
1
multivariate F distribution
Dear List,
Is there any function in R to generate multivariate F distribution with
given correlation/covariance matrix?
Actually, I just want to generate some 2-dimentional non-normal data
sets (skewed) for low (may be around 0.3 cor coeff.) negatively and also
positively correlated variables ?
Thanks in advance.
Anna
2010 Feb 19
2
problem with RGtk
Dear List,
I would like to ask about package RGtk2 with which I have a problem.
I will very much appreciate if somebody could tell me what I need to do.
I need to install a package scdMicro and it depends on gWidgetsRGtk2.
I am working on MAC, version 10.5.8.
When I try to load gWidgetsRGtk2 (or RGtk2), it asks me:
"Instal GTK+?"
I installed Gtk+ from CRAN, and added a path:
export
2008 Apr 26
0
Consistency of m-shapiro.test
Hello all,
I tried several experiments with the mshapiro.test package in R and compared
it with the energy package to test for multivariate normality and find that
the mshapiro.test is not consistent which is a bit concerning and has
suspicious behavior. On the other hand the energy test seems to be a more
appropriate test for testing multivariate normality in any dimension. I
looked for the
2008 Oct 09
1
interpreting Shapiro-Wilks test result
Hi all,
I am newbie in using R software and also doing statistical test. I want to know if my data in in normal distribution. I have 2 groups of data and I did calculate Shapiro Wilks using R software. Here is the results:
Group 1: W = 0.9206, p-value = 0.01683
Group 2: W = 0.9626, p-value = 0.4694
I am not quite sure what default confidence level (CF) is used in calculating Shapiro Wilks.
2007 Nov 17
1
save p-value in mshapiro.test(mvnormtest)
Dear all,
I want to save the p-value from mshapiro.test(mvnormtest). But mshapiro.test(mvnormtest) gives a list with class "htest" containing statistic, p.value, method and data.name as a whole.
How do I save only p-value from the result?
Thanks a lot!
2012 Mar 28
2
Test Normality
Good Night
I made different test to check normality and multinormality in my dataset,
but I donĀ“t know which test is better.
To verify univariate normality I checked: shapiro.test, cvm.test, ad.test,
lillie.test, sf.test or jaque.bera.test and
To verify multivariate normal distribution I use mardia, mvShapiro.Test,
mvsf, mshapiro.test, mvnorm.e.
I have a dataset with almost 1000 data and 9
2008 May 29
1
test for multivariate normality?
My stat textbook tells me that using Shapiro-Wilk test for each variable
one by one is not equal to a test for multivariate normality as a whole.
Does R have a function of testing for multivariate normality? Thanks.
Hongsheng (Hank) Liao, Ph.D.
Lab Manager
Center for Quantitative Fisheries Ecology
800 West 46th Street
Old Dominion University
Norfolk, Virginia 23508
Phone:757.683.4571
2006 Jun 29
0
multivariate normality test
Hello,
Could someone help me to explain the VERY big difference in applying two
tests on multivariate normality:
library(mvnormtest)
data(EuStockMarkets)
mshapiro.test(t(EuStockMarkets[15:29,1:4]))
Shapiro-Wilk normality test
data: Z
W = 0.8161, p-value = 0.005955
and
library(energy)
mvnorm.etest( EuStockMarkets[15:29,1:4] )
Energy test of multivariate normality:
2007 Oct 11
2
test for whether dataset comes from a known MVN
Dear all,
I have a multivariate dataset containing 100,000 or more points.
I want find the p-value for the dataset of points coming from a
particular multivariate normal distribution
With
mean vector u
Covariance matrix s2
So
H0: points ~ MVN( u, s2)
H1: points not ~ MVN( u, s2)
How do I find the p-value in R?
To me this is a likelihood ratio test problem.
In H0 the parameters are
2006 Jan 12
0
question for mshapiro test
Hi,
I have a question about the p-value of mshapiro test. I simulated data
from bivariate normal 1000 times and used mshapiro test to see how many
times the test would reject the null hypothesis when the p-value is 0.05.
The answer should be around 50 since the p-value is 0.05. But I got a much
higher value. Here is the R code I used and the result.
2007 May 07
4
Mardia's multivariate normality test
Dear all,
I got this error message
> library(dprep)
> mardia(Savg)
Error in cov(data) : 'x' is empty
But with the same data, I got
> library(mvnormtest)
> mshapiro.test(Savg)
Shapiro-Wilk normality test
data: Z
W = 0.9411, p-value = 0.6739
What does the error message "Error in cov(data) : 'x' is empty" mean? Thanks a lot!
Jiao
2000 Sep 25
1
Interpretation of Shapiro-Wilk
Can anybody tell me the exact meaning of the $statistic and $p.value
calculated by shapiro.test? Unfortunately it is not covered in my few
text books, and I cannot find the explanation in the R documentatiom or
on-line.
If I have a test statistic, T, which is Normally distributed with mean=m
and sd=s under the null hypothesis, then I can convert T to a p-value
(one-sided) using:
p <- pnorm(T,
1999 Nov 04
1
shapiro wilk
I'm pretty new to R and are trying to do some reliable normality
testing... but, can't find the Shapiro Wilk test in R Does some
experienced user have such a function that will be wanting to share with
me? Or there is maybe some other way to get hte Shapiro Wilk test
done... I'll appreciate any hint on this,
Thanks
--
***********************
Horacio Samaniego
Dep. Ecologia
P.
2008 Jan 13
1
Shapiro-Wilk
What is the formula used in Shapiro-Wilk Statistic?
Thanks
Eduardo (S?o Paulo/ Brazil)
2010 Feb 18
1
Shapiro-Wilk test problem
Hi everybody,
Does anyone know what problem may be with this test.
I am applying 5 different normality tests and use p-values for them, but for
some reason S-W gives me NA, while sample size is 100.
Any ideas?
Thanks a lot!
[[alternative HTML version deleted]]
2012 Apr 04
1
Shapiro-Wilk cpoefficients: 2 Qs
Greetings!
I want to have the coefficients that R uses in shapiro.test()
for the Shapiro-Wilk test for a prticular sample size, i.e.
the a[i] in
W = Sum(a[i]*x[i])/(Sum(x[i] - mean(x))^2)
(where the x[i] are sorted). Two questions:
Q1:
Is there a readymade R function from which I can extract these?
Q2:
I was wondering if I might be able to modify the code for the
function shapiro.test() so
2001 Jul 02
2
Shapiro-Wilk test
Hi,
does the shapiro wilk test in R-1.3.0 work correctly? Maybe it does, but can
anybody tell me why the following sample doesn't give "W = 1" and
"p-value = 1":
R> x<-1:9/10;x
[1] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
R> shapiro.test(qnorm(x))
Shapiro-Wilk normality test
data: qnorm(x)
W = 0.9925, p-value = 0.9986
I can't imagine a sample being
2005 Nov 09
1
Problems with Shapiro Wilk's test of normality.
Hi,
I am trying to create a table with information from Shapiro Wilk's
test of normality.
However, it fails due to lack of sample size, it says, but the way I
see it, this is not a problem.
(See the table of sample sizes (almost) at the bottom).
Applying a different function using a similar ftable call is not a
problem (See the bottom table).
This is R 2.1.0 on Linux (Gentoo).
/Fredrik
2008 Jul 14
0
"Reasonable doubt" - was "Re: shapiro wilk normality test"
>>> Ted Harding <Ted.Harding at manchester.ac.uk> 14/07/2008 00:16 >>>
>said:
>What constitutes "reasonable doubt" can become a very interesting
>question, but there are some crimes for which it has a definite
>statistical interpretation
Warning for potential courtgoers: "reasonable doubt" NEVER has a direct
statistical interpretation in a
2013 Apr 05
2
How to perform a grouped shapiro wilk test on dataframe
Hello,
I was wandering if it is possible to perform on a dataframe called 'all' a
shapiro wilk normality test for COUNTS by variable Group
ACTIVITY? Could it be done using plyer? I saw an eg that applies to an
array but not to a dataframe:
lapply(split(dataset1$Height,dataset1$Group),shapiro.test)
Any thoughts would be much appreciated.
My dataframe is in shape:
dat ACTIVIT