Re: Log-Logistic denisty function
- From: Peter Perkins <Peter.PerkinsRemoveThis@xxxxxxxxxxxxx>
- Date: Mon, 20 Mar 2006 10:03:05 -0500
Martin Fravi wrote:
In Matlab, the log-logistic distribution/denisty function has only 2
parameters (a location parameter and a scale parameter). But the
log-logistic function has also a shape parameter (see for example
www.causascientia.org/math_stat/Dists/Compendium.pdf). So I am
confused!
Martin, in addition to what Tom mentioned in his post, it's also possible that you are referring to a generalization of the logistic/log-logistic distributions in which the exponent in the denominator of the density is a positive shape parameter, rather than being fixed at the value 2. While the Statistics Toolbox does not explicitly support that generalization, it may be possible to use the "custom distribution" fitting feature of the MLE function to fit such a distribution to data, though I am not familiar enough with the distribution to know whether maximum likelihood estimation works well. It's also fairly straight-forward to create an M file that allows you to add this as a custom distribution to the DIstribution Fitting tool DFITTOOL.
Hope this helps.
- Peter Perkins
The MathWorks, Inc.
.
- References:
- Log-Logistic denisty function
- From: Martin Fravi
- Log-Logistic denisty function
- Prev by Date: Re: creating matrix in 'for loop'
- Next by Date: Re: Finding multiple equivalent values in matrix?
- Previous by thread: Re: Log-Logistic denisty function
- Next by thread: exist figure
- Index(es):
Relevant Pages
|
