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
6Kbc:w lR % tOGs80_{ ans =
V8Fp1?E9S Biva{'[m NaN
`Q@w*ta) DT Cwf 查看了一下帮助 help hygepdf
s gGXj7 L*QX21@wC HYGEPDF Hypergeometric probability density function.
5OR2\h!XZt 5p}ri,Y< Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
v/m} {&K density function at X with integer parameters M, K, and N.
w1&\heSQ Note: The density function is zero unless X is an integer.
l:i&l?>_ J_|LG rt}) The size of Y is the common size of the input arguments. A scalar input
M&v;# CV functions as a constant matrix of the same size as the other inputs.
Mxmo}tt v><c@a=[ See also hygecdf, hygeinv, hygernd, hygestat, pdf.
@| 2L>N XY h)59oM% Reference page in Help browser
aob+_9o doc hygepdf
N*w6D: MP3Vo|}3 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：
'
a>YcOw Km )VOX[ZZ http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m mM $|cge" 44x+2@&1 直到发现这个例子后才清楚各个参数所代表的具体意义。
&}y?Lt n6xJ 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?
g!\H ^d 4 v mj 'X>Q p = hygepdf(0:5,100,20,10)
3T= ?!|e f'oO/0lx p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
iCtDV5 8)o%0#;0B 详细可参见：
_t/~C*=:= http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 m4r<=o TFAd
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
GyZpdp! yp!7^ x = 0:5
Uk'bOp p = hygepdf(x,100,20,10);
Mg p+#w+, plot(x,p,':k*')
