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
p\P) Pcjrv:0$ ans =
:K~sazs7J |~o0 -: 'C NaN
<naxpflom0 fg7 查看了一下帮助 help hygepdf
sd %m{P2 @'A0Lq+# HYGEPDF Hypergeometric probability density function.
Y(u` K=* Wo(m:q(Om Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
iR"6VO density function at X with integer parameters M, K, and N.
nDS\2 Note: The density function is zero unless X is an integer.
&hUEOif y=0)vi{] The size of Y is the common size of the input arguments. A scalar input
"ql$Rz8 functions as a constant matrix of the same size as the other inputs.
^ (s(4| } eF
r,bJ See also hygecdf, hygeinv, hygernd, hygestat, pdf.
N!fjN >cw lM l'+ yy Reference page in Help browser
\ Q^grX doc hygepdf
3Vb t(K 18Vn[}]" 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：
"@^Q" RF @+0dgkJ http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m w PX^P @?jtB 直到发现这个例子后才清楚各个参数所代表的具体意义。
M0g=gmau G`;\"9t 5h 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?
dBwoAq`' uq/Fapl p = hygepdf(0:5,100,20,10)
:`4F0 ~MP |L?my p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
artn _ yh/ JHo; 详细可参见：
^i r)z@P?V http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 sH>`eqY =~" X/ >' 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
%ZcS"/gf (S4HU_,88 x = 0:5
@ l q)L p = hygepdf(x,100,20,10);
Ex Q\qp3 plot(x,p,':k*')
