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
2OlC7X{ |Pl {Oo+ ans =
F8;4Oj ;~$ $WU NaN
\bA'Furp \0T*msYQ 查看了一下帮助 help hygepdf
'p+QFT>Ca Pc4c Sw#5 HYGEPDF Hypergeometric probability density function.
)mVYqlU" -?` l<y( Y = HYGEPDF(X,M,K,N) returns the hypergeometric probability
U9sub6w 6 density function at X with integer parameters M, K, and N.
s:F+bG }| Note: The density function is zero unless X is an integer.
9+Bq00-Z$ !Ocg The size of Y is the common size of the input arguments. A scalar input
@wJa3 3QT functions as a constant matrix of the same size as the other inputs.
f8jz49C I>~BkR+u%o See also hygecdf, hygeinv, hygernd, hygestat, pdf.
t
U= b~ N%E2BJ? Reference page in Help browser
<U`Nb) & doc hygepdf
QO1Gq9 T \CQ 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：
Awf = yE: @_ ZW P http://ccpublic-1.central.cranfield.ac.uk/2001DMSOMFRC/pr062320/Matlab/stats/hygepdf.m 6v)eM=
>Mw =}g@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。
b=\3N3OX : Zo2@8@7 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?
QnLg P7Ft &YP>" < p = hygepdf(0:5,100,20,10)
p&do Qh O[B_7
p = 0.0951 0.2679 0.3182 0.2092 0.0841 0.0215
,8 ?*U]} sn`?Foh 详细可参见：
C)} LV http://www.physnet.uni-hamburg.de/physnet/matlab/help/toolbox/stats/hygepdf.html#4257 jN>UW} ? x+`3G. 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
2]f.mq_PD 3-%~{(T/ x = 0:5
#N}}8RL p = hygepdf(x,100,20,10);
uxiX"0)g > plot(x,p,':k*')
