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
z l`m1k-X c/.s`hz ans =
<WWZb\"{ /Bgqf,N | NaN
bHm/Z Zx l #C<b Dw 查看了一下帮助 help hygepdf
9ec? L >q?{'#i
/ HYGEPDF Hypergeometric probability density function.
h3E}Sa(MQ: ;~r- P$kCY Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
\nyqW4nTm density function at X with integer parameters M, K, and N.
C 8v Note: The density function is zero unless X is an integer.
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2*V 28M^ F~0 The size of Y is the common size of the input arguments. A scalar input
/+B6oE>8 functions as a constant matrix of the same size as the other inputs.
;Q&9 t fup?Mg- See also hygecdf, hygeinv, hygernd, hygestat, pdf.
#ZP F&u" /C '_-U? Reference page in Help browser
| Wck-+}U doc hygepdf
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m9/ I+W,%)vb 超几何分布参数较多，这里关于三个参数的指代不详。又在互联网上查了相关资料，包括该函数的定义式：
N!<l~[rc `K@N\VM http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m ODKh/u_ Y5ei:r|^ 直到发现这个例子后才清楚各个参数所代表的具体意义。
@N[<<k7g r/':^Ex Suppose you have a lot of 100 floppy disks and you know that 20 of them are defective. What is the probability of drawing 0 through 5 defective floppy disks if you select 10 at random?
n>B
,O .K-d p = hygepdf(0:5,100,20,10)
%@ >^JTkY8 Z$c&Y>@) p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
x]hG2on! jR:\D_: 详细可参见：
?HOnDw.v1 http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257
)bYOy+2g 0H%zkJ >Q 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
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!Q_Kil.9 x = 0:5
FeZW S>N p = hygepdf(x,100,20,10);
"ivVIq2 plot(x,p,':k*')
