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
NCKR<!( ".>#Qp% ans =
4mDHAR%D g$uiwqNA% NaN
-dM~3 ' (2;Aqx5i 查看了一下帮助 help hygepdf
]Ozz"4Z %$& eC HYGEPDF Hypergeometric probability density function.
z\|<h=EU vFe=AY<Rt| Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
MGF !ZZ\ density function at X with integer parameters M, K, and N.
&}u _e`A Note: The density function is zero unless X is an integer.
1'hpg>U WfO E I1 The size of Y is the common size of the input arguments. A scalar input
&MX&5@
Vu functions as a constant matrix of the same size as the other inputs.
:$G ^TD/n . V!5Ui< See also hygecdf, hygeinv, hygernd, hygestat, pdf.
fQ 9af)d s]m]b#1!r Reference page in Help browser
@wXYza0|d doc hygepdf
Zna6-0o e)H FI|> 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：
~ ~{lIO)& $(62j0mS> http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m C/!P&`<6 cUug}/!I 直到发现这个例子后才清楚各个参数所代表的具体意义。
t XzuP_0 Jj ]<SWh 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?
F7} yt $D`Kz*/. p = hygepdf(0:5,100,20,10)
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v& ;Z p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
+IXr4M&3 KYTXf+ oh 详细可参见：
{%wrx'< http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 s1OSuSL> Wg f
f+7 k 果然与一般对超几何分布公式字母惯常表示方式有所不同。尝试将上述分布作图如下
/*g0M2+OZo 3x(Y+
ymP x = 0:5
F~v0CBcAL p = hygepdf(x,100,20,10);
pp|$y\ZzB plot(x,p,':k*')
