Estimation of Mean and Variance of a lognormal distribution from a sample data

I have a dataset of a certain variable (100 values).

I want to find the mean and the variance of the dataset considering it follows a Lognormal distribution.

At last, I want to generate a random number from the Mean and Variance (found in the previous step).

Answer 1

[Matt J]

Formulas for the maximum likelihood estimate of the mean and variance are given here:

http://en.wikipedia.org/wiki/Log-normal_distribution#Maximum_likelihood_estimation_of_parameters

[Ashish]

I can understand the theoretical way, but a description with MATLAB would be helpful. I think that there are inbuilt functions for calculating such cases.

[Matt J]

Well, for example, the formula for the mean would be

 mu_hat= mean(log(yourData));

[Tom Lane]

This would be an estimate of the mu parameter, but that's not the mean of the lognormal. So if you really want the mean rather than mu, look elsewhere on that wikipedia page and see how to compute the mean from your mu and sigma estimates.

[Ashish]

I was able to accomplish from a document for my application. Here is the link-http://engineer.jpl.nasa.gov/practices/at2.pdf

Thanks for the help. At least your points gave me a start.