作者mangogogo (ka)
看板Statistics
标题Re: [问题] 麻烦了
时间Mon Dec 5 21:41:41 2005
※ 引述《tyrone208 (等待)》之铭言：
: The weight(in pounds)of watermelons is normally distributiond with
: mean 15 and variance 4. A packing container for several melons has a
: normal capacity of 140 pounds.What is the Maximum number of melons that
: should be placed in a single packing container if the normal weight limit
: is to be exceeded only 5% of the time?
: 求样本数 但是想了很久想不出来
: 可以帮小弟解惑一下吗 谢谢
X_i->iid N(15,4) i=1,2,3,...,n
S=ΣX_i->N(15n,4n)
BY CLT
P{S<140}=P{S-15n/2√n < 140-15n/2√n}=0.95
P{Z<140-15n/2√n}=0.95
140-15n/2√n=1.645
n=6.98
取n=6为最大
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1F：推 tyrone208:感恩感恩 小弟懂了 12/05 22:55