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        Probability density function for the Beta distribution
        
         
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          Permission is granted to copy, distribute and/or modify this document under the terms of the  GNU Free Documentation License, Version 1.2 or any later version published by the  Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled  GNU Free Documentation License.  http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue 
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        gnuplot source under GPL:
dbeta(x,a,b) = exp((a-1)*log(x)+(b-1)*log(1-x)-lgamma(a)-lgamma(b)+lgamma(a+b))
pbeta(x,a,b) = ibeta(a,b,x)
set samples 1001
set terminal postscript enhanced colour solid lw 2 "Times-Roman" 20
set output
set xrange [0:1]
set xtics 0.1
f(x,y,z) = dbeta(x,y,z)
set yrange [0:2.6]
set ytics 0.2
set key 0.61,2.4
#f(x,y,z) = pbeta(x,y,z)
#set ytics 0.1
#set key 0.21,0.94
plot \
    f(x, 0.5,0.5) title "{/Symbol a} = {/Symbol b} = 0.5", \
    f(x, 5,  1)   title "{/Symbol a} = 5, {/Symbol b} = 1", \
    f(x, 1,  3)   title "{/Symbol a} = 1, {/Symbol b} = 3", \
    f(x, 2,  2)   title "{/Symbol a} = 2, {/Symbol b} = 2", \
    f(x, 2,  5)   title "{/Symbol a} = 2, {/Symbol b} = 5" lt 7
         
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          This work is  free software; you can redistribute it and/or modify it under the terms of the  GNU General Public License as published by the  Free Software Foundation; either version 2 of the License, or any later version. This work is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See  version 2 and  version 3 of the GNU General Public License for more details.http://www.gnu.org/licenses/gpl.htmlGPLGNU General Public Licensetruetrue | 
         
        
        
        
        
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