Displaying 20 results from an estimated 5000 matches similar to: "generate correlated dataset"
2003 Jul 11
2
using SVD to get an inverse matrix of covariance matrix
Dear R-users,
I have one question about using SVD to get an inverse
matrix of covariance matrix
Sometimes I met many singular values d are close to 0:
look this example
$d
[1] 4.178853e+00 2.722005e+00 2.139863e+00
1.867628e+00 1.588967e+00
[6] 1.401554e+00 1.256964e+00 1.185750e+00
1.060692e+00 9.932592e-01
[11] 9.412768e-01 8.530497e-01 8.211395e-01
8.077817e-01 7.706618e-01
[16]
2008 Nov 11
1
simulate data with binary outcome and correlated predictors
Hi,
I would like to simulate data with a binary outcome and a set of predictors that are correlated. I want to be able to fix the number of event (Y=1) vs. non-event (Y=0). Thus, I fix this and then simulate the predictors. I have 2 questions:
1. When the predictors are continuous, I can use mvrnorm(). However, if I have continuous, ordinal and binary predictors, I'm not sure how to simulate
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
2012 Jul 04
2
How to generate a correlated binary data set?
Hi.
I am trying to generate a correlated binary data set.
I've tried to use mvtBinaryEP, binarySimCLF, and bindata packages but none
of them works in R version 2.15.1.
Do you know any package to generate correlated binary covariates and work
in R version 2.15.1, or how to generate it?
Thanks,
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2009 Feb 02
2
how to generate multiple random variables that are correlated
Hi.
I have two variables, x and y, that are each normally distributed with
mean 0 and have known standard deviations. The variables also have a
known correlation, so I can represent their correlations in a matrix
like so:
a <- array(c(0.3,0.1,0.1,0.2),c(2,2))
a
Is there an R function that generates random values for my two
variables given the correlation? I'd like to do this for up to
2012 Dec 02
2
How to simulate correlated data
Hello there,
I would like to simulate X --Normal (20, 5)
Y-- Normal (40, 10)
and the correlation between X and Y is 0.6. How do I do it in R?
Thank you very much
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2005 Dec 15
5
How to simulate correlated data
Hello there,
I would like to simulate X --Normal (20, 5)
Y-- Normal (40, 10)
and the correlation between X and Y is 0.6. How do I do it in R?
Thank you very much
Lisa Wang Msc.
Princess Margaret Hospital
Toronto, Ca
2005 Dec 01
1
Simulate Correlated data from complex sample
Dear List:
I have created some code to simulate data from a complex sample where
5000 students are nested in 50 schools. My code returns a dataframe with
a variable representing student achievement at a single time point. My
actual code for creating this is below.
What I would like to do is generate a second column of data that is
correlated with the first at .8 and has the same means within
2011 Aug 11
5
generate two sets of random numbers that are correlated
Dear R users
I'd like to generate two sets of random numbers with a fixed correlation
coefficient, say .4, using R.
Any suggestion will be greatly appreciated.
Regards,
Kathryn Lord
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2003 Dec 03
1
Simulating correlated distributions
Hi
How can one simulate correlated distributions in R for windows?
Coomaren P. Vencatasawmy
---------------------------------
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2007 Jun 12
4
Generating artificial datasets with a specific correlation coefficient.
I need to create artificial datasets with specific correlation
coefficients (i.e. a dataset that returns r = 0.30, etc.) as examples
for a lab I am teaching this summer. Is there a way to do that in R?
Thanks.
Jim Milks
Graduate Student
Environmental Sciences Ph.D. Program
136 Biological Sciences
Wright State University
3640 Colonel Glenn Hwy
Dayton, OH 45435
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2010 Feb 28
1
Gradient Boosting Trees with correlated predictors in gbm
Dear R users,
I’m trying to understand how correlated predictors impact the Relative
Importance measure in Stochastic Boosting Trees (J. Friedman). As Friedman
described “ …with single decision trees (referring to Brieman’s CART
algorithm), the relative importance measure is augmented by a strategy
involving surrogate splits intended to uncover the masking of influential
variables by others
2007 Nov 16
1
generate multivariate F with specified correlation matrix
Dear all,
In MATLAB, to generate multivariate F with specified correlation matrix Pn I can use the code such as
Z = mvnrnd([0 0 0 0 0], Pn, N);
U = normcdf(Z,0,1);
X = [finv(U(:,1),5,15) finv(U(:,2),5,15) finv(U(:,3),5,15) finv(U(:,4),5,15) finv(U(:,5),5,15)];
Is there something similar in R?
Thank you for your time.
2009 Feb 12
3
get top 50 correlated item from a correlation matrix for each item
Hi,
I have a correlation matrix of about 3000 items, i.e., a 3000*3000
matrix. For each of the 3000 items, I want to get the top 50 items that
have the highest correlation with it (excluding itself) and generate a
data frame with 3 columns like ("ID", "ID2", "cor"), where ID is those
3000 items each repeat 50 times, and ID2 is the top 50 correlated items
with ID,
2010 Aug 24
3
generate random numbers from a multivariate distribution with specified correlation matrix
Hi all,
rmvnorm()can be used to generate the random numbers from a multivariate
normal distribution with specified means and covariance matrix, but i want
to specify the correlation matrix instead of covariance matrix for the
multivariate
normal distribution.
Does anybody know how to generate the random numbers from a multivariate
normal distribution with specified correlation matrix? What about
2010 Jan 21
1
correlation significance testing with multiple factor levels
[Apologies in advance if this is too "statistics" and not enough "R".]
I've got an experiment with two sets of treatments. Each subject either received
all treatments from set A or all treatments from set B.
I can compute the N pairwise correlations for all treatments in either set using
cor(). If I take the mean of these N pairwise correlations, I see that the
effects
2011 May 07
1
generate multiple mvrnorm samples using apply-like
I want to generate multiple multivariate normal samples with different
mean vectors
and common covariance matrix.
I can do this with a loop, but can't quite figure out how to do it with
apply and friends.
In the example below, I want values to have 3 columns: group, x, y
# number of groups, and group means
x <- jitter(seq(2,10,by=2))
y <- x + rnorm(length(x), 0, .5)
means <-
2004 Jun 25
2
Simulating from a Multivariate Normal Distribution Using a Correlation Matrix
Hello,
I would like to simulate randomly from a multivariate normal distribution using a correlation
matrix, rho. I do not have sigma. I have searched the help archive and the R documentation as
well as doing a standard google search. What I have seen is that one can either use rmvnorm in
the package: mvtnorm or mvrnorm in the package: MASS. I believe I read somewhere that the latter
was
2008 Jun 16
0
Creating correlated multivariate dataset
Hello list,
I am trying to test a model but for the beginning I want to do this by using simulated dataset. The model is
Y_t = X_t %*% beta + e
Where Y : (Nx1); X: (Nxp); beta: (0.6,0.3,0.1); e-uncorrelated normally distributed variates for each t. and later I want to use to use this dataset in a BUGS model to estimate the betas.
Thank you for you consideration.
[[alternative
2007 Mar 23
1
generating lognormal variables with given correlation
Dear R users
I use simulated data to evaluate a model by sampling the parameters in
my model from lognormal distributions.
I would like these (lognormal distributed) parameters to be correlated,
that is, I would like to have pairwise samples of 2 parameters with a
given correlation coefficient.
I have seen that a covariance matrix can be fixed when generating random
variables from a