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# wexpstat

## PURPOSE

Mean and variance for the Exponential distribution.

## SYNOPSIS

[m,v]= wexpstat(m0);

## DESCRIPTION

``` WEXPSTAT Mean and variance for the Exponential distribution.

CALL:  [m,v] = wexpstat(m0)

m, v = the mean and variance, respectively
m0 = parameter of the Exponential distribution, m0>0.

Mean (m) and variance (v) for the Exponential distribution is

m=m0  and  v=m0^2;

Example:
[m,v] = wexpstat(5)```

## CROSS-REFERENCE INFORMATION

This function calls:
 error Display message and abort function. nan Not-a-Number.
This function is called by:

## SOURCE CODE

```001 function [m,v]= wexpstat(m0);
002 %WEXPSTAT Mean and variance for the Exponential distribution.
003 %
004 % CALL:  [m,v] = wexpstat(m0)
005 %
006 %   m, v = the mean and variance, respectively
007 %     m0 = parameter of the Exponential distribution, m0>0.
008 %
009 %  Mean (m) and variance (v) for the Exponential distribution is
010 %
011 %  m=m0  and  v=m0^2;
012 %
013 % Example:
014 %   [m,v] = wexpstat(5)
015
016 % Reference: Johnson, Kotz and Balakrishnan (1994)
017 % "Continuous Univariate Distributions, vol. 1", p. 494 ff
018 % Wiley
019
020 % Tested on; Matlab 5.3
021 % History:
022 % revised pab Dec2003
023 % fixed a bug k1->k3
024 % revised pab 24.10.2000
027
028 error(nargchk(1,1,nargin))
029
030 % Initialize fm to zero.
031 m = zeros(size(m0));
032 v=m;
033
034 k=find(m0 > 0);
035 if any(k),
036   m(k) =  m0(k);
037   v(k) = m0(k).^2;
038 end
039
040 k3 = find(m0<0 );
041 if any(k3)
042   tmp = NaN;
043   m(k3) = tmp(ones(size(k3)));
044   v(k3)=m(k3);
045 end
046
047```

Mathematical Statistics
Centre for Mathematical Sciences
Lund University with Lund Institute of Technology

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