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
-*3wNGh { V7.EDE2A3 ans =
Pr" 2d\ l = #uy NaN
'w DNP_ v~j21` 查看了一下帮助 help hygepdf
~%'M[3Rb hW]:CIqk HYGEPDF Hypergeometric probability density function.
M Su_*&j9T YOqBIbp~&) Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
4Xlq
Ym density function at X with integer parameters M, K, and N.
(2 X`imJ Note: The density function is zero unless X is an integer.
XB2[{XH, ?EdF&^[3rD The size of Y is the common size of the input arguments. A scalar input
2\_}81 hM functions as a constant matrix of the same size as the other inputs.
kd2+k4 @# +as(m See also hygecdf, hygeinv, hygernd, hygestat, pdf.
-B'<*Y N|wI=To Reference page in Help browser
C/!kMMh>vV doc hygepdf
X180_Kt2 (wke o{lx 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：
Bf.@B0\ t
?rUbN http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m K.B!-< THC34u] 直到发现这个例子后才清楚各个参数所代表的具体意义。
U2seD5I Pi`}-GUe, 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?
ry0P\wY} y\]:&)?&C^ p = hygepdf(0:5,100,20,10)
~0eJ6i *Mk5*_
p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
!{jDZ?z{h C0J/FFBQ ^ 详细可参见：
@uApm~} http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 @-)jU! U,\3 !D0jt 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
I'm.+(1m, 3U ^E<H x = 0:5
~"xc
3(h p = hygepdf(x,100,20,10);
xj\! Sn2 plot(x,p,':k*')
