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
rd{( E 8ipLq`) ans =
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" sA .yb,Fw 查看了一下帮助 help hygepdf
Km -B=6*QY 6B{Awm@v}X HYGEPDF Hypergeometric probability density function.
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k%c7 XQ8Imkc Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
II ZsN*^ density function at X with integer parameters M, K, and N.
vxx3^;4p Note: The density function is zero unless X is an integer.
=
xk @ Q7$ y"ck;OQD The size of Y is the common size of the input arguments. A scalar input
,YTIYG]( functions as a constant matrix of the same size as the other inputs.
DBRJtU!5x H"l'E9k.&p See also hygecdf, hygeinv, hygernd, hygestat, pdf.
b.;W|$ . 3F1Z $d( Reference page in Help browser
!A o?bs' doc hygepdf
!TF VBK !: 5n 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
:83" t-O8[ Zpmy)W]1
http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m #UQ[8e X c^~|%+ 直到发现这个例子后才清楚各个参数所代表的具体意义。
k|5nu-B0v 7Go!W(8 Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
U9w*x/S wb xjN~Y D: p = hygepdf(0:5,100,20,10)
uM8gfY)OI "K< VZ p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
`O/)q^m1L U?QO'H 5 详细可参见：
&bRH(yF http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 %}[??R0 l ;uEw 果然与一般对超几何分布公式字母惯常表示方式有所不同。尝试将上述分布作图如下
5z _) F@BNSs N= x = 0:5
@!$NUY8,A# p = hygepdf(x,100,20,10);
x-<dJ}` plot(x,p,':k*')
