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
5]mH.{$x$? 42e [OG - ans =
wmpQF< uj;i E
9 NaN
5NkF_&S_1 y%|E z 查看了一下帮助 help hygepdf
L@RnLaoQ C;ab -gh HYGEPDF Hypergeometric probability density function.
O0y0'P-rJq ;{8 X+H Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
ke@OG! M / density function at X with integer parameters M, K, and N.
_W@sFv%sj Note: The density function is zero unless X is an integer.
[#wt3<d`) .|"E:qTD The size of Y is the common size of the input arguments. A scalar input
W +Piqf* functions as a constant matrix of the same size as the other inputs.
C!_=L?QT^ c}v8j2{ See also hygecdf, hygeinv, hygernd, hygestat, pdf.
[-`s`g- ^?|4<Rm Reference page in Help browser
*56j'FX doc hygepdf
wo62 R&ac IUAe6 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：
Jj% xLv% l`75 BR http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m &n]v K}q5,P ( 直到发现这个例子后才清楚各个参数所代表的具体意义。
< =!t!_ DmWa!5 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?
+dCR$<e9r `4 ga~Ch p = hygepdf(0:5,100,20,10)
5~>j98K Na]IT CVR p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
b4$g$() 9k4z__K e 详细可参见：
y s) http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 ">B&dNrt -5os0G80 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
+U'n|>t9 3 p -SpUvp x = 0:5
^-Ks_4 p = hygepdf(x,100,20,10);
oGXc u?ft plot(x,p,':k*')
