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
d6u L;eR nF=h|rN ans =
wEdXaOEB5 ,$*$w< NaN
>scEdeM !O*\|7A( 查看了一下帮助 help hygepdf
Yt &^ i( 'Ic$p> HYGEPDF Hypergeometric probability density function.
/MA 4Er r nfc&.(6x< Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
Rt+s\MC^r density function at X with integer parameters M, K, and N.
-q[?,h Note: The density function is zero unless X is an integer.
%N 2=: ;f ZZ.GpB. The size of Y is the common size of the input arguments. A scalar input
O `*}N1No[ functions as a constant matrix of the same size as the other inputs.
^27r-0|l^ }z}oVc See also hygecdf, hygeinv, hygernd, hygestat, pdf.
0N md*r zI&oZH^v n Reference page in Help browser
+g(QF doc hygepdf
9%|!+!j <J\z6+,4E 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
0C7x1 : fxjs "rD5 http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m L \pe ^dQ#\uy 直到发现这个例子后才清楚各个参数所代表的具体意义。
TeQpmhN 7Y:1ji0 l Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
@`)A ) |[ 8&5[); p = hygepdf(0:5,100,20,10)
I
U/gYFT 8@Pv
nO L p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
S_WYU&8
t;{/Q&C 详细可参见：
t=5 K#SX} http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 q'[5h>Pa g$~ktr+% 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
>A#]60w. Yz4Q!tL x = 0:5
@a+1Ri`) p = hygepdf(x,100,20,10);
"d9"Md0k plot(x,p,':k*')
