Displaying 20 results from an estimated 10000 matches similar to: "quantile of a mixture of bivriate normal distributions"
2009 Mar 29
1
Quantiles for bivariate normal distribution
Hi,
Does anyone know how to write a R function to solve the quantile c for the
following equation.
P(Z1>1.975, Z2<c)+ P(Z1>c, Z2>c)=0.05/6.
Z1 and Z2 have a bivariate normal distribution with mean 0, variance 1 and
correlation 0.5.
Thanks a lot!
Hannah
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2010 Jun 18
1
question in R
Dear all,
I am trying to calculate certain critical values from bivariate normal
distribution (please see the
function below).
m <- 10
rho <- 0.1
k <- 2
alpha <- 0.05
## calculate critical constants
cc_z <- numeric(m)
var <- matrix(c(1,rho,rho,1), nrow=2, ncol=2, byrow=T)
for (i in 1:m){
if (i <= k) {cc_z[i] <- qmvnorm((k*(k-1))/(m*(m-1))*alpha,
2004 Nov 18
1
gibbs sampling for mixture of normals
hi
i'm looking for a gibbs sampling algorithm for R for the case of mixture of K
normals, and in particular for the case of bivariate normals.
i'd be grateful if anyone could send its own R-routine, at least for the
univariate case.
thank you in advance
matteo
2009 May 21
1
em algorithm mixture of multivariate normals
Hi,
I would like to know if it is possible to have a "R code" to estimate the
parameters of a mixture of bivariate (or multivariate) normals via EM
Algorithm. I tried to write it, but in the estimation of the matrix of
variance and covariance, i have some problems. I generate two bidimensional
vectors both from different distribution with their own vector means and
variance and
2012 Sep 13
2
simulate from conditional distribution
Dear all,
Y, X are bivariate normal with all the parameters known.
I would like to generate numbers from the distribution Y | X > c
where c is a constant.
Does there exist an R function generating
random numbers from such a distribution?
Thank you very much.
hannah
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2013 Mar 18
2
Fit a mixture of lognormal and normal distributions
Hello
I am trying to find an automated way of fitting a mixture of normal and log-normal distributions to data which is clearly bimodal.
Here's a simulated example:
x.1<-rnorm(6000, 2.4, 0.6)x.2<-rlnorm(10000, 1.3,0.1)X<-c(x.1, x.2)
hist(X,100,freq=FALSE, ylim=c(0,1.5))lines(density(x.1), lty=2, lwd=2)lines(density(x.2), lty=2, lwd=2)lines(density(X), lty=4)
Currently i am using
2003 Nov 19
0
'nor1mix' for 1-dimensional normal mixture distributions
I have been authoring a very small R package on CRAN, named
"normix" which implements an S3 class "norMix" has plot and
print methods; further, E[X] and Var[X] methods, random number
generation ("r") and density evaluation.
It also provides the 16 "Marron-Wand densities" (known in the (1d)
density estimation business).
Erik J?rgensen has provided
2003 Nov 19
0
'nor1mix' for 1-dimensional normal mixture distributions
I have been authoring a very small R package on CRAN, named
"normix" which implements an S3 class "norMix" has plot and
print methods; further, E[X] and Var[X] methods, random number
generation ("r") and density evaluation.
It also provides the 16 "Marron-Wand densities" (known in the (1d)
density estimation business).
Erik J?rgensen has provided
2003 Sep 01
0
Quantile Regression Packages
I'd like to mention that there is a new quantile regression package
"nprq" on CRAN for additive nonparametric quantile regression estimation.
Models are structured similarly to the gss package of Gu and the mgcv
package of Wood. Formulae like
y ~ qss(z1) + qss(z2) + X
are interpreted as a partially linear model in the covariates of X,
with nonparametric components defined as
2004 Nov 16
2
help on EM Algorithm for bivariate normal
Hi,
I woul like to know if it is possible to have a "R code" to generate EM
Algorithm for a normal bivariate mixture.
Best regard,
S.F.
2006 Feb 08
1
Mixture normal distribution
Dear R helper,
I hope that u can help me to sort out my problem
because I sent an E-mail last night to R-list but I
have not receive any help and at the same time I think
this problem is not so hard.
I have used the following functions before
> K<-10
> prime<-c(2,3,5,7,11,13,17)
> UN<-seq(1:K)%*%t(sqrt(prime))
> U1<-UN-as.integer(UN)
> U<-matrix(qnorm(U1),K,7)
2007 Apr 20
1
Estimating a Normal Mixture Distribution
Hi everyone,
I am using R 2.4.1 on a MacOS X ("Tiger") operating system. In the
last few day I was trying to estimate the parameters of a mixture of
two normal distributions using Maximum Likelihood.
The code is from Modern Applied Statistics with S (4th edition),
chapter 16 ("Optimization"), the dataset is available under MASS in
R. Unfortunately, when I tried out the
2009 Aug 06
0
Fitting Mixture of Non-Central Student's t Distributions
Dear Ingmar & Dave,
Thanks a lot for your help and sorry for the late reply.
Finally, I've found a way to separate the mixture of distributions
(empirically). But the gamlss package looks great, I'm sure it will help
me during my further studies.
Kind regards,
Susanne
On 15 Jun 2009, at 20:09, Ingmar Visser wrote:
> Dear Susanne & Dave,
>
> The gamlss package family
2011 Oct 19
1
Estimating bivariate normal density with constrains
Dear R-Users
I would like to estimate a constrained bivariate normal density, the
constraint being that the means are of equal magnitude but of opposite
signs. So I need to estimate four parameters:
mu (meanvector (mu,-mu))
sigma_1 and sigma_2 (two sd deviations)
rho (correlation coefficient)
I have looked at several packages, including Gaussian mixture models in
Mclust, but I am not sure
2012 Mar 05
1
Fitting & evaluating mixture of two Weibull distributions
Hello,
I would like to fit a mixture of two Weibull distributions to my data, estimate the model parameters, and compare the fit of the model to that of a single Weibull distribution.
I have used the mix() function in the 'mixdist' package to fit the mixed distribution, and have got the parameter estimates, however, I have not been able to get the log-likelihood for the fit of this model
2006 May 11
2
Maximum likelihood estimate of bivariate vonmises-weibull distribution
Hi,
I'm dealing with wind data and I'd like to model their distribution in
order to simulate data to fill-in missing values. Wind direction are
typically following a vonmises distribution and wind speeds follow a
weibull distribution. I'd like to build a joint distribution of
directions and speeds as a VonMises-Weibull bivariate distribution.
First is this a stupid question? I'm
2008 Apr 03
1
How to ask for *fixed* number of distributions under parameterized Gaussian mixture model.
Dear R users:
I am wondering how to ask for *fixed* number of distributions under
parameterized Gaussian mixture model.
I know that em() and some related functions can predict the
parameterized Gaussian mixture model. However, there seems no
parameter to decide number of distributions to be mixed (if we known
the value in advance).
That is, assume I know the (mixed)data is from 3 different
2011 Apr 22
1
How to generate normal mixture random variables with given covariance function
Dear All,
Suppose Z_i, i=1,...,m are marginally identically distributed as a two normal mixture p0*N(0,1) + (1-p0) *N( miu_i, 1) where miu_i are identically distributed according to a mixture and I have generated Z_i one by one .
Now suppose these m random variables are jointly m-dimensional normal with correlation matrix M= (m_ij).
How to proceed next or how to start correctly ?
Question:
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
2017 Nov 17
0
Multivariate mixture distributions
Hello, I am searching for a way to generate random values from a multivariate mixture distribution. For starters, one could create a mixture distribution consisting of a gamma or normal distribution and then a tail/spike of values in a normal distribution (eg as in Figure 1,?A Eyre-Walker, PD Keightley. 2007. The distribution of fitness effects of new mutations. Nature Review Genetics 8: 610-618)