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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X 查看了一下帮助 help hygepdf
1 I_q3 { ]#.&f]6l HYGEPDF Hypergeometric probability density function.
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(Nb1R"J ` Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
U&$]?3? density function at X with integer parameters M, K, and N.
MToQ8qKs Note: The density function is zero unless X is an integer.
,{*f Opn #!,`EU The size of Y is the common size of the input arguments. A scalar input
guXp HF= functions as a constant matrix of the same size as the other inputs.
{Y%=/ba W Bqlc+d: See also hygecdf, hygeinv, hygernd, hygestat, pdf.
2{I z /,Id_TTCO Reference page in Help browser
B1#>$"_0}= doc hygepdf
Jjh!/pWZ4 L6=RD<~C 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：
#@s~V<rW r~_ /Jj http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m g
'a? E*CQG;^=N 直到发现这个例子后才清楚各个参数所代表的具体意义。
Ytwv=;h- TbAdTm W 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?
Atq2pL" GSnHxs) p = hygepdf(0:5,100,20,10)
)ZyuF(C& >/kG5]zxY p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
'N ::MN p sy(]Pf 详细可参见：
P\6T4s http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 |Umfq:W`y_ KqUSTR1e[ 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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Nl x = 0:5
:42;c:8 5 p = hygepdf(x,100,20,10);
y"L`bl A9} plot(x,p,':k*')
