Random Number Generator - Log Pearson Type III Distribution



The Log Pearson Type III distribution is commonly used in hydraulic studies. It is somehow similar to normal distribution, except instead of two parameters, stanand deviation and mean, it also has skew.  When the skew is small, Log Pearson Type III distribution approximates normal. 

The following example shows input and output from 3 simulations.  Each has the same mean and standard deviation, but with different skew.  The objective is to show the change in the distribution when skew changes.  All three simulations have 10,000 iterations and alpha of 5% (for 1 tail test).

The output shows the estimate of skewness, mean, stand deviation, maximum value, minimum value, lower confidence interval, and upper confidence interval from each of the 3 simulations (these returned estimates can be used to check it the random numbers generator works the way it is instructed to do).

The following shows the charts generated from the 3 simulations.  The charts show as skew decreases, the distribution becomes more normal.

* Complete program (with open source codes) available in Package Set 2 and the Combo Package.