[問題] 信賴區間
題目為
A study was conducted in a large city following the dramatic increase in
coffee price during the final quarter of 2003. The objective was to compare
the mean supermarket prices of the "four" leading brands at the end of the year.
"Eight" supermarkets in the city were selected, and the price per pound was
recorded for each brand. The mean square of prices for brands was .05 and
that for supermarkets was .03. The total sum of squares of prices was .45.
A. Are the average prices of coffee the same for the eight supermarket?
Use α = .05
B. Are the average prices of coffee the same for the four brands?
Use α = .05
C. Find a 90% confidence intervals for the difference in the mean price of
Brand A and Brand B if he sample mean price of Brand A was $2.43 and that
of Brand B was $2.49.
D. List the assumption required for the above tests.
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A和B是用ANOVA表去算出F值
F(brands)=11.628
F(supermarkets)=6.977
然後用H0和H1去做有沒有全等的檢定
算出A B 皆在拒絕域 AcH1
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C.2.43-2.49 +/- t 0.95(21)√(0.0043/4 + 0.0043/4)
D.常態性 同質性 獨立性
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C的區間估計不太確定
請問大家這樣步驟有沒有問題
感謝
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