R help - Oct 2010 - Generate variable with Bivariate Normal Distribution

Dear All

    I want to generate variable with Bivariate Normal Distribution by 
use mean1 = a, variance1 = b, mean2 = c, variance2 = d, rho = e.

     How I can do this.

Many Thanks.

IRD 		 	   		  
	[[alternative HTML version deleted]]

You could e.g. use the package "mvtnorm" (not horribly fast, but
handy):

(assuming that rho is the correlation)

library("mvtnorm")
m <- c(mean1, mean2) #mean vector
cov <- rho*sqrt(variance1*variance2)
sig <- matrix(c(variance1, cov, cov, variance2), nrow=2) #covariance matrix
rmvnorm(100, mean=m, sigma=sig)

alternatively, you can transform manually via sigma^(1/2) (faster). This is
covered
in almost any (multivariate) statistics book.

Gregor


On Wed, 20 Oct 2010 12:29:53 +0700
??????????????????? ???????????????????????????? <ird_ubru at hotmail.com>
wrote:
> 
> Dear All
> 
>     I want to generate variable with Bivariate Normal Distribution by 
> use mean1 = a, variance1 = b, mean2 = c, variance2 = d, rho = e.
> 
>      How I can do this.
> 
> Many Thanks.
> 
> IRD 		 	   		  
> 	[[alternative HTML version deleted]]
> 
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