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
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m'.wh| 查看了一下帮助 help hygepdf
g4Z Uh@b~ Jinh#iar HYGEPDF Hypergeometric probability density function.
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fX Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
HUx`RX0> density function at X with integer parameters M, K, and N.
XY'= _5t Note: The density function is zero unless X is an integer.
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k$ cN d&C'/N The size of Y is the common size of the input arguments. A scalar input
.:?v;rYk{ functions as a constant matrix of the same size as the other inputs.
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F;/ -9dZT See also hygecdf, hygeinv, hygernd, hygestat, pdf.
"p O 8w:ay,= Reference page in Help browser
eX$KH;M doc hygepdf
9Kd=GL_ GN|"RuQ 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：
qArR5OJ Nr*l3Z>LD http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m OL\-SQ& &4OJJ9S 直到发现这个例子后才清楚各个参数所代表的具体意义。
i*|HN"! zbFy3-R P 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?
I"> "> WXx nOLJr p = hygepdf(0:5,100,20,10)
r-T 1^u 4 ?BQ&d p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
g"/n95k< E{V?[HcWq 详细可参见：
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q.8~Z http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 bhUE!h< x@Gg fH<l 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
/kGWd9ujF t`6]eRR x = 0:5
9Z -2 MF p = hygepdf(x,100,20,10);
0o8`Y plot(x,p,':k*')
