[問題] 標準差
題目上不太懂怎麼做 因為不懂s的分佈 為甚麼會N(σ,σ^2/2(n-1))
Normal的話 那是用Z嗎 還是用t@@
It is known thae the point estimator toward population standard deviation
σ is the sample standard deviation s.This estimator is biased and has a
complicated sampling distribution.However, when the sample size n is large,
the sampling distribution of s can be shown to follow N(σ,σ^2/2(n-1))
approximately.
(1) Construct a formula of the 100(1-α)% confidence interval
for σ in this case.
(2)Sometimes, it is desired to control the sampling error within a level e
by choosing an appropriate sample size.With a planning value for σ
from past experience and a confidence coefficient 1-α,derive the
minimum sample size required.
(3)Consider the hypothesis test about σ. If we feel that current σ would
be smaller from past experience,what are the appropriate hypotheses?
With type I risk specified as α,what is the critical region to reject
null hypothesis(in the form of s>c or s<c)?
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 220.133.229.161
※ 編輯: selient 來自: 220.133.229.161 (08/30 17:42)
推
08/30 22:14, , 1F
08/30 22:14, 1F
→
08/30 22:21, , 2F
08/30 22:21, 2F
→
08/30 22:22, , 3F
08/30 22:22, 3F
討論串 (同標題文章)