[R] Bivariate lognormal distribution
Spencer Graves
spencer.graves at pdf.com
Fri Mar 25 15:40:50 CET 2005
I hope Professor Ripley will correct me if I'm mistaken, but the
documentation for "mvrnorm" in library(MASS) says it will, "Simulate
from a Multivariate Normal Distribution". If you want the density
function or probabilities or quantiles, you can get those from
library(mvtnorm).
Just for completeness, to use normal for a lognormal, you need to
take the logarithms of your number (which must be all positive; zeros
and negative numbers become NA), then compute mean vector and variance
matrix of the logs, compute probabilities on the log scale, then back
transform by exponentiating to get the results back into the original
scale.
hope this helps. spencer graves
Prof Brian Ripley wrote:
> On Thu, 24 Mar 2005, Vicky Landsman wrote:
>
>> Is there a package that enables to create the bivariate log-normal
>> variables?
>
>
> Just exponentiate each of a bivariate normal pair. You can get the
> latter from mvrnorm in package MASS.
>
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