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
U5] pi +r s ncIqsZ ans =
c=6Q%S Y=
7%+WyD NaN
P &)1Rka S', 9g4(5 查看了一下帮助 help hygepdf
zLD| /` $y?k[Y-~ HYGEPDF Hypergeometric probability density function.
f2,1<^{ ItX5JV) Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
$oLU; q% density function at X with integer parameters M, K, and N.
SjEdyN# Note: The density function is zero unless X is an integer.
9% IlW Oc&),ru2l The size of Y is the common size of the input arguments. A scalar input
]p~IYNl2%j functions as a constant matrix of the same size as the other inputs.
i\H+X S
}>n1F_ See also hygecdf, hygeinv, hygernd, hygestat, pdf.
Fn^C{p^ E&B{5/rv Reference page in Help browser
|7^^*UzSK: doc hygepdf
ba@ =^Fa; )n=ARDd^e 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：
ofW+_DKB?l >x[`;O4 http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m M"_FrIO YGsS4ia*4i 直到发现这个例子后才清楚各个参数所代表的具体意义。
0
3~ Ikll ^\:2}4Uj_ 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?
qXXGF_Q M_ ``'gw p = hygepdf(0:5,100,20,10)
uvA(Rn s~},y ]YV p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
@1R8 -aa-r .~}z4r 详细可参见：
%TrF0{NR90 http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 s{/qS3= ,kgF2K! 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
yW.COWL=) 5A&y]5-Q` x = 0:5
%q_ M iu@ p = hygepdf(x,100,20,10);
x:t<ZG&Xwg plot(x,p,':k*')
