Re: Landau mean value

On 7 Feb 2007, at 14:41, Y. Roed wrote:

> Hi,
> I'm working on my diploma thesis evaluating nuclear physics data
> with root.
>
> When I fit a Landau function to my histogram with fixed upper and
> lower limits
> the fit parameters show the most probable value, the sigma, the
> chisquare, and
> the constant. Is there a possibility to get the mean value either
> printed in
> the parameter list or shown in the root command line?
>
> With respect to the question from 2002 (see below) is there a
> function that
> gives a relation between these two values when having fixed limits?
> Unfortunately, the question hasn't been discussed further on.

There is no easy function. The mean of the Landau will depend where you put your limits.
If you don't have limits the mean will diverge. To get the value you should compute numerically the integral using the truncated Landau distribution.

  Best Regards,
  Lorenzo
>
> Yours, Yvonne
>
> Hi jacek,
> Does it make sense? The mean value depends where you cut the tails
> Rene Brun
> On Thu, 28 Nov 2002, Jacek M. Holeczek wrote:
>> Hi,
>> Just a stupid question ...
>> Is there any easy formula that gives the relation between the
>> Landau's
>> Most Probable Value and its Mean Value ?
>> Thanks in advance,
>> Jacek.
>
> *******************************************************
> Yvonne Roed
> Institut fuer Experimentelle und Angewandte Physik,
> University of Kiel
> Leibnizstrasse 11,
> D-24118 Kiel
> Germany
> phone: (+) 49 431 880 2543; Fax: (+) 49 431 880 3968
> e-mail: roed_at_physik.uni-kiel.de
> www: www.ieap.uni-kiel.de/et
>
Received on Wed Feb 07 2007 - 16:20:19 CET