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
$RunGaX!=N Z9*@w`x^u ans =
2+b}FVOe\ TtH!5{$s NaN
/0$405 n, LM"N:
查看了一下帮助 help hygepdf
* dk(<g=fM -@Urq>^v T HYGEPDF Hypergeometric probability density function.
u^#e 7u q~Al[`K Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
Le{.B@2-" density function at X with integer parameters M, K, and N.
B !wr} ] Note: The density function is zero unless X is an integer.
n)z:C{ I6gduvkXi4 The size of Y is the common size of the input arguments. A scalar input
E@#<p-@~ functions as a constant matrix of the same size as the other inputs.
5uOz #hN 3+vVdvu% See also hygecdf, hygeinv, hygernd, hygestat, pdf.
-M _>]ubG x9S9%JG : Reference page in Help browser
9\T9pjdZE doc hygepdf
2;J\Z=7 >oaL -01i 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
TCIbPs E ;*ULrX4[ http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m wXKt)3dm u MZB}O"
r 直到发现这个例子后才清楚各个参数所代表的具体意义。
ckv8QAm H
SGz- Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
s&<76kwl k g Rys p = hygepdf(0:5,100,20,10)
jzZ]+'t N8x.D-=gG p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
B@VAXmCaoV 45$aq~%as 详细可参见：
%+<1X?;,Fq http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 ,'9R/7%s 8V9OMOt! 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
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1[1 K5\l
(BB x = 0:5
z|Yt|W p = hygepdf(x,100,20,10);
; sq xFF@ plot(x,p,':k*')
