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
iaGA9l<b o`T.Zaik, ans =
Jo? LPR
\6 Tx rW69FV7 NaN
Cxf K(F M/ 3;-g 查看了一下帮助 help hygepdf
v%tjZ5x N$fP\h^AR HYGEPDF Hypergeometric probability density function.
wNB?3v{n kmQ:wf: Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
HqGI. density function at X with integer parameters M, K, and N.
OC ! {8MR Note: The density function is zero unless X is an integer.
2&6D`{"P K\xz|Gq The size of Y is the common size of the input arguments. A scalar input
fu7x,b0p functions as a constant matrix of the same size as the other inputs.
t]xz7 VQ z#{Y>.b See also hygecdf, hygeinv, hygernd, hygestat, pdf.
c <TEA LkbD='\= Reference page in Help browser
~WrpJjI[ doc hygepdf
+3,7 Apj [* xdILj 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
2/SUEnaLy_ %1&X+s3 http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m xQR/Xp!h Df"PNUwA" 直到发现这个例子后才清楚各个参数所代表的具体意义。
Y3@+a A [8u9q.IZ Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
L7ae6#5. 3MQHoxX p = hygepdf(0:5,100,20,10)
D#nH g <?41-p-; p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
m mF0RNE BOpZ8p'eH1 详细可参见：
(XK,g;RoEn http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 UDHOcb JCH9~n. 果然与一般对超几何分布公式字母惯常表示方式有所不同。尝试将上述分布作图如下
rDl/R^w" yb pOk x = 0:5
[l=@b4Og p = hygepdf(x,100,20,10);
5$i(f8* plot(x,p,':k*')
