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Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 已解決
Yahoo!奇摩知識+ - 分類問答 - 科學常識 - 已解決 
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統計學尋求解答.....急件.....有勞各位能者
Nov 27th 2013, 01:15

1.
題目A,C需假設母體為常態分配,否則需知母體分配再解.
以下A,C係假設母體為常態分配
Sol:
A
設隨機變數為X, 其平均數為Xbar
母體常態,σ已知,Xbar之分佈屬常態
由H1知此為雙尾檢定
臨界值為 -Z 0.025 = -1.96 , Z 0.025 = 1.96
B
n = 35≧30
依中央極限定理,Xbar之分佈屬常態
由H1知此為右尾檢定 
臨界值為Z 0.01 = 2.326
C
母體常態,σ未知,小樣本, Xbar之分佈屬 t分配 
由H1知此為左尾檢定  
臨界值為 - t 0.01(16-1) = - 2.602
D
n = 49 ≧30
依中央極限定理,Xbar之分佈屬常態
由H1知此為左尾檢定 
臨界值為 -Z 0.05 = - 1.645
Ans:
A.  -1.96 , 1.96 
B.  2.326
C.  - 2.602
D.  - 1.645
( A,C之解係假設母體為常態分配,否則題目需列出母體分配,再解 )

2.
題目沒說清楚 8.2 , 5.6 代表什麼
但從前後文推測應該是分別代表男女的飲酒量"平均值"
H0 : μ1-μ2 = 0
H1 : μ1-μ2
- Z 0.025 = - 1.96 , Z 0.025 = 1.96
檢定的統計量
= ( 8.2 - 5.6 ) /√(5.9^2/54 + 5.7^2/85
≒ 2.566 > 1.96
故拒絕H0,接受H1,即男性和女性的飲酒量有顯著差異.
95%的信賴區間
= ( 8.2 - 5.6 )± Z 0.025√(5.9^2/54 + 5.7^2/85
= 2.6± 1.96*1.013343
≒ 0.614 ~ 4.586
Ans:
A.  H0 : μ1-μ2 = 0 , H1 : μ1-μ20
B.  - 1.96 , 1.96
C.  獨立,因為屬不同群體
D.  2.566
E.  拒絕H0,接受H1,即男性和女性的飲酒量有顯著差異
F.  ( 0.614 , 4.586 ) 

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