Displaying 20 results from an estimated 5000 matches similar to: "question for mshapiro test"
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!
2005 May 03
1
multivariate Shapiro Wilks test
Hello,
I have a question about multivariate Shapiro-Wilks test.
I tried to analyze if the data I have are multivariate normal, or how
far they are from being
multivariate normal. However, any time I did
>mshapiro.test(mydata)
I get the message:
Error in solve.default(R %*% t(R), tol = 1e-18) :
system is computationally singular: reciprocal condition number
= 5.38814e-021
I tried
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:
2013 Mar 18
0
Problem with generated parameter estimates
Dear All,
I would be very grateful for your help concerning the following question:
Below mentioned programme is available on net to generate longitudinal
data. Usually we get almost same parameter estimates as used to generate
the data. The problem here is I am not able to get it for data used here,
despite increasing sample size and number of simulations. Is it normal to
expect this type of
2007 Dec 17
2
regression towards the mean, AS paper November 2007
Dear friends, regression towards the mean is interesting in medical
circles, and a very recent paper (The American Statistician November
2007;61:302-307 by Krause and Pinheiro) treats it at length. An initial
example specifies (p 303):
"Consider the following example: we draw 100 samples from a bivariate
Normal distribution with X0~N(0,1), X1~N(0,1) and cov(X0,X1)=0.7, We
then calculate
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
2003 Sep 01
0
Re: Plotting bivariate normal distributions.
You'll find that it is a lot easier to do it in R:
# lets first simulate a bivariate normal sample
library(MASS)
bivn <- mvrnorm(1000, mu = c(0, 0), Sigma = matrix(c(1, .5, .5, 1), 2))
# now we do a kernel density estimate
bivn.kde <- kde2d(bivn[,1], bivn[,2], n = 50)
# now plot your results
contour(bivn.kde)
image(bivn.kde)
persp(bivn.kde, phi = 45, theta = 30)
# fancy contour with
2008 Oct 04
3
How to plot countours with fixted densities?
Hello,
I used the following codes to generate bivariate normal dependence structure with unit Frechet margins.
Sigma <- matrix(c(1,.5*sqrt(1),.5*sqrt(1),1),2,2) # generate
y <- mvrnorm(Nsam, c(0,0), Sigma) # random
v <- cbind(pnorm(y[,1],mean = 0, sd = 1), pnorm(y[,2],mean = 0, sd = 1))
z <- cbind(-1/log(v[,1]),-1/log(v[,2]))
z1 <- z[,1]
z2 <- z[,2]
And to
2011 May 16
3
Simulating correlations with varying sample sizes
Hi there,
I would like to draw 10 correlations from a bivariate population - but every
draw should be done with a different sample size. I thought I could to this
with a loop:
r=numeric(10) #Goal vector
N = c(1000,100,80,250,125,375,90,211,160,540) #Sample size vector
for(i in 1:10) {
data <- mvrnorm(n=N,mu=c(0,0),Sigma=matrix(c(1,.3,.3,1),2))
r[i] <- cor(data[,1],data[,2])
}
2008 May 16
0
How to determine sensible values for 'fnscale' and 'parscale' in optim
Dear R-help,
I'm using the 'optim' functions to minimise functions, and have read the
documentation, but I'm still not sure how to determine sensible values to
use for the 'fnscale' and 'parscale' options.
If I have understood everything correctly, 'fnscale' should be used to scale
the objective function, so that for example if the default is
2005 Mar 08
1
3D plot not working as desired!
Hello R-users!
I am trying to plot 3 vectors (x,y,z) of observations
generated by mvrnorm in library(MASS).
I tried plot3d in library(djmrgl) and scatterplot3d.
But these program gives x,y,z axis which do not
intersect at the origin (0,0,0).
I searched through all the graphics related packages
for R like xgobi, ggobi, grid and more. Quite
confusing which one to choose.
Would anyone recommend
2007 May 17
1
3d graph question
Hi, this is simple,
I've generated a bivariate normal distribution with a known correlation.
I want to plot the density function with p(y,x) on the vertical axis
and x, and y on the horizontal axes. How is that done? Thanks in advance!
library(MASS)
mu <- c(0,1) # mean vector
sigma <- matrix(c(1,.8,.8,1), ncol=2)
tmp <- mvrnorm(1000, mu, sigma)
cor(tmp)
2010 Apr 06
2
checking bivariate normality
x <- iris$Sepal.Length[1:50]/iris$Sepal.Width[1:50]
y <- iris$Petal.Length[1:50]/iris$Petal.Width[1:50]
I want to check whether (x,y) follows a bivariate normal distribution or
not, using density plot or scatter plot. Is it possible to plot a bivariate
density in R. I cant find any.
Arindam Fadikar
M.Stat
Indian Statistical Institute.
New Delhi, India
[[alternative HTML version
2000 Jan 12
0
Problems creating a random sample
> Date: Wed, 12 Jan 2000 13:05:21 +0100 (CET)
> From: Adriane Leal <loparic at student.fsa.ucl.ac.be>
> To: r-help at stat.math.ethz.ch
> Subject: [R] Problems creating a random sample
>
> Hi!
>
> I'm supposed to create a random sample bivariate normal variates of size
> equal to 250 with mean vector (-1,1) and cov matrix (1,0.95,0.95,1)
>
> In S
2008 Feb 24
0
problem with ML estimation
dear list,
as a part my problem. I have to estimate some parameters using ML
estimation. The form of the likelihood function
is not straight forward and I had to use a for loop to define the function.
I used "optim" to maximise the result but
was not sure of the programme.
To validate my results, I tried to write a function to obtain the MLE of a
bivariate normal in the same manner.
On
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
2007 Sep 17
1
Create correlated data with skew
Hi all,
I understand that it is simple to create data with a specific
correlation (say, .5) using mvrnorm from the MASS library:
> library(MASS)
> set.seed(1)
>
> a=mvrnorm(
+ n=10
+ ,mu=rep(0,2)
+ ,Sigma=matrix(c(1,.5,.5,1),2,2)
+ ,empirical=T
+ )
> a
[,1] [,2]
[1,] -1.0008380 -1.233467875
[2,] -0.1588633 -0.003410001
[3,] 1.2054727 -0.620558768
2005 Mar 24
2
Bivariate lognormal distribution
Dear experts!
Is there a package that enables to create the bivariate log-normal variables?
Thanks a lot,
Vicky Landsman.
[[alternative HTML version deleted]]
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
2012 Dec 01
1
Simulation in R
Hello!
How can I do 100 simulations of length 17 from bivariate bivariate normal
distribution, if I know all 5 parameters?
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