看板Statistics
标 题[问题]gamma distribution
发信站无名小站 (Sun Apr 20 16:42:01 2008)
转信站ptt!Group.NCTU!grouppost!Group.NCTU!wretch
As part of a grand opening promotion, a department store has advertised that
every 1000th purchase made on opening day will be given to the customer for
free. The store expects 5 purchases to be made every minute. Let X be the
time (in minutes) from opening until the first free purchase is given away.
Ans: X ~ Gamma(a, l) with a=1000 and l=5. (An alternative answer that is
acceptable is Exponential(l) with l=1/(1000/5)=1/200.)
答案
X ~ Gamma(a, l) with a=1000 and l=5
是以1人0.2分钟来看
请问若我以5人为一单位
那麽X~Gamma(200,1)
但为什麽不行呢？
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 123.195.50.65
1F：→ HERMAN06:以5个人为单位时 每个单位应该是服从 Gamma(5,5)04/18 23:01
2F：→ algebra1029:对啊 5人单位 并不服从 Exp(1) 而是服从 Gamma (5,5)04/18 23:19
3F：→ Arton0306:抱歉 还是不懂 5人为一单位 那X表一单位要等几分钟04/19 12:53
4F：→ Arton0306:为何X~Exp(1)是不对的？？ 04/19 12:54
--
夫兵者不祥之器物或恶之故有道者不处君子居则贵左用兵则贵右兵者不祥之器非君子
之器不得已而用之恬淡为上胜而不美而美之者是乐杀人夫乐杀人者则不可得志於天下
矣吉事尚左凶事尚右偏将军居左上将军居右言以丧礼处之杀人之众以哀悲泣之战胜以
丧礼处之道常无名朴虽小天下莫能臣侯王若能守之万物将自宾天地相合以降甘露民莫
之令而自均始制有名名亦既有夫亦将知止123-195-50-65.dynamic.kbronet.com.tw海