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
( }5k"9Z $zbm!._~DA ans =
:x] gTZ? J`;G9'n2 NaN
$@+\_f'bU> pq+Gsu1^ 查看了一下帮助 help hygepdf
&CF74AN# 6T&6N0y+9 HYGEPDF Hypergeometric probability density function.
WZdA<<,:o Lo @mQ Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
YMad]_XOP density function at X with integer parameters M, K, and N.
{ ; );E Note: The density function is zero unless X is an integer.
U L$^zR3%d "m0 >u,HmI The size of Y is the common size of the input arguments. A scalar input
@~'c (+<3 functions as a constant matrix of the same size as the other inputs.
rPkV=9ull, #J eZA0r5 See also hygecdf, hygeinv, hygernd, hygestat, pdf.
KWCA9.w4q AnG/A!G Reference page in Help browser
CT3wd?)z` doc hygepdf
-#j-Zo+< o;M"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：
fy YT #r ["Ep.7=SU http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m !0 `44Gbq 5W> i'6* 直到发现这个例子后才清楚各个参数所代表的具体意义。
nsij;C g&O%qX- 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?
BQ,]]}e43z 2 0d[\P(. p = hygepdf(0:5,100,20,10)
=B4mi.;@i .1 .n{4z>: p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
0XSZ3dY&+ @fRB0m"3 详细可参见：
v )!Rir5 http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 3X89mIDr Uc!} D 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
fBS;~;l $dFEC}1t
x = 0:5
%L}9nc%~eP p = hygepdf(x,100,20,10);
25t2tj@S plot(x,p,':k*')
