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
Uwg*kJ3H j>#ywh*A ans =
zG\: #,9 uuYeXI; NaN
0}WDB_L 9z7rv, 查看了一下帮助 help hygepdf
hSG1f` YFeL #) 5y HYGEPDF Hypergeometric probability density function.
ap Wv+A 64t: Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
a$$aM2 .2 density function at X with integer parameters M, K, and N.
O8/r-?4. Note: The density function is zero unless X is an integer.
4c@_u8 t_ id/ The size of Y is the common size of the input arguments. A scalar input
FA1h!Vit functions as a constant matrix of the same size as the other inputs.
uIR/^o _xr@dK<
See also hygecdf, hygeinv, hygernd, hygestat, pdf.
8p PQ G| qsJ Reference page in Help browser
-Awk P doc hygepdf
,y gDNF [I78<IJc 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 /4 A5RM&y http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m cq}i)y 1Sd<cOEd 直到发现这个例子后才清楚各个参数所代表的具体意义。
;Hn>Ew CQH^VTQ 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?
+<fT\Oq# @s|yH " p = hygepdf(0:5,100,20,10)
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!u3\91 ko6[Ej:TBo p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
hI,+J> ]fJ9.Js 详细可参见：
O&r9+r1` http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 C5~
+"#B M2LW[z 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
!&pk^VFl+ p/KG{-f, x = 0:5
_C@<*L=Q p = hygepdf(x,100,20,10);
&_,.*tha plot(x,p,':k*')
