在用
Matlab绘制各种常用概率分布的密度函数时，都比较简单，唯独超几何分布试了几次都不成功，输出结果总是
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W; yNg 查看了一下帮助 help hygepdf
d` %8qLIW +Z> Y// HYGEPDF Hypergeometric probability density function.
I,TJV)B fFDI qX Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
TR P#b 7nC density function at X with integer parameters M, K, and N.
~A@T_ *0 Note: The density function is zero unless X is an integer.
Y Xz*B5R %J(y2 } The size of Y is the common size of the input arguments. A scalar input
8=QOp[w functions as a constant matrix of the same size as the other inputs.
Ne<={u% 1P4cB w% See also hygecdf, hygeinv, hygernd, hygestat, pdf.
Z/ -9 G a%| I'r Reference page in Help browser
g_X-.3=2K doc hygepdf
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c j/.$ (E 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
8 Na.H::cZ @Wgd(Ezd http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m 4<V%7z_.B 0R HKzk6~c 直到发现这个例子后才清楚各个参数所代表的具体意义。
bfo..f-0/Y A*+pGQ Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
;f;A" [|iWLPO1&k p = hygepdf(0:5,100,20,10)
}9:( l =MR.*m { p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
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\^o8qw'pt 详细可参见：
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http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 &10l80vj _{j'` # 果然与一般对超几何分布公式字母惯常表示方式有所不同。尝试将上述分布作图如下
/ILj}g' w8=&rzr8 x = 0:5
s!k7Wwj p = hygepdf(x,100,20,10);
x,wXR=H plot(x,p,':k*')
