R help - Aug 2012 - log-normal distribution fitting with expected value = 1

Dear R users,
I would like to estimate mu and sigma of a log-normal distribution, where I
know that the expected value is 1, as it is a normalized distribution. That
means as E(x) = exp (mu + 1/2*sigma^2) = 1 that 2*mu = -sigma^2 . Therefore
I only need to fit one parameter either sigma or mu. How could I do this in
R?
Thank you very much for your help!
biophil

	[[alternative HTML version deleted]]

Take a look at

fitdist

in the MASS package.

Cheers,
Michael

On Wed, Aug 22, 2012 at 4:23 AM, Biophil <biophilo at gmail.com>
wrote:
> Dear R users,
> I would like to estimate mu and sigma of a log-normal distribution, where I
> know that the expected value is 1, as it is a normalized distribution. That
> means as E(x) = exp (mu + 1/2*sigma^2) = 1 that 2*mu = -sigma^2 . Therefore
> I only need to fit one parameter either sigma or mu. How could I do this in
> R?
> Thank you very much for your help!
> biophil
>
>         [[alternative HTML version deleted]]
>
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http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

On Aug 22, 2012, at 2:23 AM, Biophil wrote:
> Dear R users,
> I would like to estimate mu and sigma of a log-normal distribution,  
> where I
> know that the expected value is 1, as it is a normalized distribution.
Are you sure that is what "normalized distribution" actually means in
the context you are reading it? I would have assumed that it meant  
that the integral over its domain equaled 1, which is quite different  
than its mean equaling 1.
> That
> means as E(x) = exp (mu + 1/2*sigma^2) = 1 that 2*mu = -sigma^2 .  
> Therefore
> I only need to fit one parameter either sigma or mu. How could I do  
> this in
> R?
> Thank you very much for your help!
> biophil
>
-- 

David Winsemius, MD
Alameda, CA, USA