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
Z{x)v5yh2V nWA>u J5 ans =
[ps4i_ d|>/eb.R NaN
D7=Irz!O\7 jXPbj. 查看了一下帮助 help hygepdf
wV-9T*QrM pfHfw ,[ HYGEPDF Hypergeometric probability density function.
#_ Wk V TjHt:%7. Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
l+j
!CvtI density function at X with integer parameters M, K, and N.
3n~ O&{ Note: The density function is zero unless X is an integer.
-kHJH><j {vdY( The size of Y is the common size of the input arguments. A scalar input
u;+8Jg+xH/ functions as a constant matrix of the same size as the other inputs.
_r>kR 7A\{ Q ]e]\J See also hygecdf, hygeinv, hygernd, hygestat, pdf.
HuR774 f[ EvH/d4V; Reference page in Help browser
>>|47ps3 doc hygepdf
#}l$<7Z U W 8F@nY 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：
bOSqD[? =J|jCK[r http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m &j,# 5f( ESU O 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。
e ?FQ6 ? L/In~' *- 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?
g#`}HuPoE AN3oh1xe: p = hygepdf(0:5,100,20,10)
HJBGxy w Kp^"<%RT p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
41P0)o Kwi+}B ! 详细可参见：
',/# | http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 9MH;=88q aRElk&M 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
] >1`Fa6_ *6eJmbFG x = 0:5
=CO) Q2 p = hygepdf(x,100,20,10);
Bh'!aip k plot(x,p,':k*')
