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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L@R_D ' 4,y 查看了一下帮助 help hygepdf
b-2pzcK{# k]t,q$Vd HYGEPDF Hypergeometric probability density function.
]9#CVv[rq U&`6&$] Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
Ywmyr[ Uh' density function at X with integer parameters M, K, and N.
YXgWH'i~ Note: The density function is zero unless X is an integer.
:,jPNuOA EG%I1F% The size of Y is the common size of the input arguments. A scalar input
DQ%`v = functions as a constant matrix of the same size as the other inputs.
ix:2Z- KuIkul9^% See also hygecdf, hygeinv, hygernd, hygestat, pdf.
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c^rC8E Reference page in Help browser
nT_*EC<. doc hygepdf
tsc k|;v kea e.6[ 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：
u$ap H{ 7F"3 <U@J http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m "v@);\-V 1]"D %U= 直到发现这个例子后才清楚各个参数所代表的具体意义。
H3!,d`D.N pi|\0lH6W 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?
52da]BW< , <7" K& p = hygepdf(0:5,100,20,10)
f+{c1fb>s 0Wjd-rzc, p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
#c6ui0E%;t X";TZk 详细可参见：
7F,07\c http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 ,NjX&A @ th5
X? so 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
dz{#"No0 Dq{: R x = 0:5
(}9cD^F0n p = hygepdf(x,100,20,10);
+G<}JJ'V plot(x,p,':k*')
