作者sploo (正確的方向決定一切)
看板graduate
標題[請益] 統計考古題的問題
時間Wed Jan 30 21:27:52 2013
主要是問C小題的問題
其他的不知道有沒有寫對
請高手幫忙
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.
====================================================
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
C.一開始先用Ho H1檢定"變異數"有沒有相等
拒絕域 CR:{Fo< F0.025(3,7)=0.1698,Fo<F0.975(3,7)=5.89}
接下來不知道該怎麼用ANOVA表的東西寫出 Fo
D.常態性 同質性 獨立性
感謝
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◆ From: 220.132.123.76
※ 編輯: sploo 來自: 220.132.123.76 (01/30 21:34)
1F：→ sevres:假設brand a,brand b樣本數分別為na,nb，然後scheffe's? 01/30 22:10
2F：→ sevres:題目好像沒有給na,nb，所以好像也算不出來?個人淺見 01/30 22:11
3F：推 ethefalse:他只有要求單純的CI吧?就直接用一般的CI 變異數用MSE代 01/30 22:24
4F：→ ethefalse:個人看法-.-" 01/30 22:24
5F：推 robinlee:不用檢定變異數 ANOVA已經假定變異數相同了 01/30 22:30
6F：→ robinlee:直接求Scheffe's區間 na=nb=8 01/30 22:31
7F：→ robinlee:如果用Scheffe's法求算 答案應該是(-0.1473, 0.0273) 01/30 22:43
8F：→ robinlee:有錯請指教 謝謝 01/30 22:44
9F：→ sploo:也是算一樣的答案 我把他想的太複雜 這題應該是一因子集區 01/30 22:52
※ 編輯: sploo 來自: 220.132.123.76 (01/30 23:05)
10F：推 ethefalse:可以請教一下為什麼要用Scheffe嗎@@? 01/30 23:23
11F：→ sploo:單一是事前檢定 sch是事後 第二題我檢定是接受H1 為了找出 01/30 23:47
12F：→ sploo:不全等 所以用sch 有錯請指教 01/30 23:48
13F：推 goshfju:C.題目沒有要你檢定變異數 (請看D. 你已經假設相等了) 01/31 00:47
14F：→ goshfju:他只是要普通的信賴區間 不是要兩兩比較用的聯合信賴區間 01/31 00:48
15F：→ goshfju:所以就算一般的信賴區間就好了 01/31 00:49
16F：推 kobebryant08:第4題的假設應該有飽含變異數相等 01/31 01:22