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
ygp NMq#?X P\H$*6v( ans =
vvG#O[| O )b AcU NaN
j kIgEF2d* . ),m7"u| 查看了一下帮助 help hygepdf
f~? MNJ2 2^7VDqLc HYGEPDF Hypergeometric probability density function.
4jl-? 5zF7yvS.w Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
;HeUD5Nt6F density function at X with integer parameters M, K, and N.
Hi<5jl Note: The density function is zero unless X is an integer.
paW7.~3
R p9)'nU'\t The size of Y is the common size of the input arguments. A scalar input
W`-AN}C# functions as a constant matrix of the same size as the other inputs.
< J Q vuC T/&4lJ^2l^ See also hygecdf, hygeinv, hygernd, hygestat, pdf.
v [ 4 J0 <OEu 4,~: Reference page in Help browser
W]rK* Dc doc hygepdf
5l"v : Px 1 yN/+Rq 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
>{^&;$G+* /K 9T n http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m ,$96bF "# <x),HTJ 直到发现这个例子后才清楚各个参数所代表的具体意义。
+mN]VO*y 0ZXG{Gp9S Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
IOsitMOX: =5jX#Dc5.+ p = hygepdf(0:5,100,20,10)
>8nRP%r[5, bi bjFg p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
t .&YD x Q!: J.J 详细可参见：
gI
q YIt http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 nDS mr G.,dP +i 果然与一般对超几何分布公式字母惯常表示方式有所不同。尝试将上述分布作图如下
z5v)~+"1 io$!z=W x = 0:5
a 8Jn.! p = hygepdf(x,100,20,10);
S& % G B plot(x,p,':k*')
