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
JNh=fvO2i G1}~.% J ans =
No:^hY:F8 n!GWqle NaN
CN$I:o04C ?n!lU r$:y 查看了一下帮助 help hygepdf
y^2#9\}K :3JCvrq HYGEPDF Hypergeometric probability density function.
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9q?$V( Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
Mv|vRx^b density function at X with integer parameters M, K, and N.
31WZJm^ Note: The density function is zero unless X is an integer.
`SCy<w3$+[ c p$.,V The size of Y is the common size of the input arguments. A scalar input
iJ}2"i7 M functions as a constant matrix of the same size as the other inputs.
fD'/#sA#' :`D'jF^S See also hygecdf, hygeinv, hygernd, hygestat, pdf.
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*_ Reference page in Help browser
S|HY+Z6n' doc hygepdf
:]'q#$! P3G:th@j= 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：
] bIt@GB 1Yud~[c http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m :3v9h^|+ S#k{e72 * 直到发现这个例子后才清楚各个参数所代表的具体意义。
g[M]i6h2 qYx!jA]O 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?
^%;" [r 29%=: *R$ p = hygepdf(0:5,100,20,10)
]3}feU+ ! Q!&CG5l p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
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K 详细可参见：
%*6RzJO6 http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 L/BHexOB yr5N Rs 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
cv= \g Z ?9p$XG x = 0:5
Mq@}snp"S p = hygepdf(x,100,20,10);
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HI plot(x,p,':k*')
