推 andypard2000:我覺得是0.5 =1.96 *(4/ n^0.5 )，確定題目沒打錯? 12/31 21:36
我想問一下，這題是不是解答寫錯了
以下是題目↓
The article "Evaluating Tunnel Kiln Performance" gave the following
simmary information for fracture strengths (MPa) of n = 169
ceramic bars fired in a particular kiln : (x bar) = 89.10
s=3.73
Suppose the investigators had believed a priori that the population
standard deviation was about 4 MPa .
Based on this supposition , how large a sample would have been required to
estimate μ to within 0.5 MPa with 95% confidence?
我的算法是
0.5 = 2 *1.96 *(4/ n^0.5 )
解答寫
0.5 = 1.96 * (0.16 / n^0.5)
奇怪？為什麼是0.16?
為什麼沒乘2 ?
題目不是說 standard deviation was about 4 MPa . ????
感謝!!
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