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
#H&`wMZZ: h|XLL| : ans =
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Oh/2$72 dnstm@0k 查看了一下帮助 help hygepdf
5J m %*Wb Wf5ohXm> HYGEPDF Hypergeometric probability density function.
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f VTwJtWnq Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
TW~9<c density function at X with integer parameters M, K, and N.
LV$`bZ Note: The density function is zero unless X is an integer.
uz[5h0c <#No t 1R The size of Y is the common size of the input arguments. A scalar input
FdM xw*} functions as a constant matrix of the same size as the other inputs.
! F~*Q2PZ9 _J -3{a See also hygecdf, hygeinv, hygernd, hygestat, pdf.
[E4 #|w a29 rD$ Reference page in Help browser
ff.;6R\ doc hygepdf
Yp8GW1@ J? 84WS 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：
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% +oR wXO3W http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m ,[|4{qli \ EmubpUS ; 直到发现这个例子后才清楚各个参数所代表的具体意义。
7~7_T#dTh `=VN\W^& 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?
8^av &u$ Q:sw*7" F p = hygepdf(0:5,100,20,10)
R,KoymXP 4/ M ~# p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
<t) D`nY\ tP]-u3 详细可参见：
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HN http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 6A*k ,pMH` 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
CiTjRJ-ZW) o@blvW<v7 x = 0:5
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R<q[@)F p = hygepdf(x,100,20,10);
3F|#nq plot(x,p,':k*')
