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
OAkZKG| 5r8< 7g:>C ans =
9Ujo/3,Ak z'\_jaj^ NaN
J | bd)0 @u]rWVy;\[ 查看了一下帮助 help hygepdf
kDN:ep{/ cm[&? HYGEPDF Hypergeometric probability density function.
ZR]25Y y $?<Z!*x Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
a8iQ4
density function at X with integer parameters M, K, and N.
Oz`BEy b]{ Note: The density function is zero unless X is an integer.
NzSoqh{R #( jw!d& The size of Y is the common size of the input arguments. A scalar input
Vq\ `+&A functions as a constant matrix of the same size as the other inputs.
au=o6WRa 2h1C9n%j9 See also hygecdf, hygeinv, hygernd, hygestat, pdf.
K]0:?h;%Ld *HO}~A%Lx Reference page in Help browser
/bi[ e9 R doc hygepdf
`t9?=h! O_ DtvjI' 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：
x+x40!+\ 0# &5.Gr) http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m
L0@SCt Ry K\uv 直到发现这个例子后才清楚各个参数所代表的具体意义。
(>GK \=:< I@%t.%O Jp 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?
L>%o[ tS ^1aAjYFn p = hygepdf(0:5,100,20,10)
2hkRd>)&5 A1#%`^W9 p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
$!(pF J}+6 UlD 详细可参见：
DRgTe&+ http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 Z2='o_c j eX^}]x|% 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
}mdAM6 mfo1+owT x = 0:5
^[X YFQ TL p = hygepdf(x,100,20,10);
hn= [1<#^( plot(x,p,':k*')
