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
BbIg]E/G |S6L[Uo ans =
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@f!r"P] NaN
OC6v%@xa \yhj {QS.k 查看了一下帮助 help hygepdf
Xk>Yi V",? \x=j HYGEPDF Hypergeometric probability density function.
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VX Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
B<{Yj }.. density function at X with integer parameters M, K, and N.
GT 5J` Note: The density function is zero unless X is an integer.
dKp Uw9C#/ =G\N1E The size of Y is the common size of the input arguments. A scalar input
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functions as a constant matrix of the same size as the other inputs.
{> Yna"p \=2<<
iv See also hygecdf, hygeinv, hygernd, hygestat, pdf.
itmFZZh >F5E^ DY Reference page in Help browser
jn]:*i;i doc hygepdf
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Ba_.]x 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：
RI2 /h rW Gd Vrl[ http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m (zml704dI) s 9n_s=w 直到发现这个例子后才清楚各个参数所代表的具体意义。
kInU,/R* Dqg01_O9O 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?
X?aj0# Q w 6 p = hygepdf(0:5,100,20,10)
cU_:l.b aZ'(ar : p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
* "d['V3 _ SJ Fuv/ 详细可参见：
2-dEie/{' http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 %~I%*=o[ ` InBhU> 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
6<o2 0(? VmON}bb[zz x = 0:5
b ^q%p 1 p = hygepdf(x,100,20,10);
"IJ 9vXI plot(x,p,':k*')
