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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ans =
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Ru@ { b` p|Qn?^C: 查看了一下帮助 help hygepdf
2?@Ozr2Uh zKfY0A R HYGEPDF Hypergeometric probability density function.
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Uh DLPg0>;jl Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
<Yn-sH density function at X with integer parameters M, K, and N.
jIck! Note: The density function is zero unless X is an integer.
YI?t mqzt ZuT5}XxF The size of Y is the common size of the input arguments. A scalar input
1!;4I@W(I) functions as a constant matrix of the same size as the other inputs.
+LF`ZXe8l <Aqo['] See also hygecdf, hygeinv, hygernd, hygestat, pdf.
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v') b\p2yJ\ Reference page in Help browser
K "8 ! doc hygepdf
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+!i6!6r 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：
m8Rt>DY IHv>V9yiG http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m Qn}M 4VhKV JX 直到发现这个例子后才清楚各个参数所代表的具体意义。
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KJ 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?
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TA7JA p = hygepdf(0:5,100,20,10)
7MIrrh k 0+NGFX \p p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
,Bl_6ZaL *d:$vaL 详细可参见：
$V ;0z~&!' http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 x!fgZr{ w[#*f?at~ 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
\"b'Z 2 g VYk UUp x = 0:5
^G NL:D%6d p = hygepdf(x,100,20,10);
c9Q _Qr0' plot(x,p,':k*')
