University Stat. - LQ1

👨🏻‍🏫 學術台數學

STEVIE-G™

2009-10-06 4:33 am

As follows: (answer in details)

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/01-63.jpg

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/02-57.jpg

圖片參考：http://i707.photobucket.com/albums/ww74/stevieg90/03-46.jpg

更新1:

For the pic of part ii, please visit http://i707.photobucket.com/albums/ww74/stevieg90/02-57.jpg

更新2:

(i),(ii):(a)-(c)只要ANS (ii)(d)及(e)要steps

更新3:

myisland兄,仲有e part>

回答 (1)

myisland8132

2009-10-09 4:34 am

✔ 最佳答案

(i)(a) mean=32.0833
E(X^2)=1058.25
Var(X)=28.9119,standard deviation=5.377
(b) median=(32+34)/2=33
first quartile=(25+30)/2=27.5
third quartile=35.5
(c) A bell shaped
(ii)(a) P(Z>(30-20)/5)=P(Z>2)=0.02275
(b) 1-(0.97725)^5=0.10869
(c) Since P(-0.5244<Z<0.5244)=0.4
-0.5244<(X-20)/5<0.5244
17.378<X<22.622
(d) mean=20=>the answer is 19-21

2009-10-09 14:11:54 補充：
(e) Here (Z_0.05)(s/√n)<=2 where Z_0.05=1.645,s=10

(1.645)(10/√n)<=2

n>=67.65

At least 68 samples are needed

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