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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Uc3-n`C 79 svlq= 查看了一下帮助 help hygepdf
lV0\UySH h^ D]@H HYGEPDF Hypergeometric probability density function.
m% {4 ' `*{ig Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
YIQm;E EG density function at X with integer parameters M, K, and N.
~KufSt * Note: The density function is zero unless X is an integer.
2AAZZx +$ ?T(>! m The size of Y is the common size of the input arguments. A scalar input
T&] J3T FJ functions as a constant matrix of the same size as the other inputs.
=a<};X z|V5/" See also hygecdf, hygeinv, hygernd, hygestat, pdf.
%dM P}k/ W5_:Q @ Reference page in Help browser
|Gv WHe` doc hygepdf
s=+,F<;x.U c v b:FK 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：
R`F54?th Qw ukhD7 http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m KKd S h1 9$ z|k wU 直到发现这个例子后才清楚各个参数所代表的具体意义。
y0d a8sd) dT%$"sj5 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?
=Kv*M @ R N1q/H | p = hygepdf(0:5,100,20,10)
?Sq?f? 6_m5%c~;+r p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
}jQxw i) hy"O_Le 详细可参见：
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g.3 http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 * ?a-m\ cViEvS r 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
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Rv2 H+`s#'(i_P x = 0:5
QQso<.d & p = hygepdf(x,100,20,10);
iwnctI plot(x,p,':k*')
