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Unformatted text preview: The Hong Kong University of Science & Technology ISMT 111: Business Statistics Tutorial Set 6 Con f dence Interval Estimation for Mean, μ • — For large sample size ( n > 30) , if σ is unknown, use s instead. — For small sample size ( n 6 30) with normal population and known σ . A (1 − α )100% Con f dence Interval for μ is X ± z α 2 σ √ n . • — σ 2 is unknown — small sample size ( n 6 30) — population is normal A (1 − α )100% Con f dence Interval for μ is X ± t n − 1 , α 2 s √ n , where X the point estimator of μ z α 2 it corresponds to an area of 1 − α 2 from the center of a standardized normal distribution t n − 1 , α 2 it corresponds to an area of 1 − α 2 from the center of a t distribution,with n − 1 degree(s) of freedom (d.f.) 1 − α Con f dence Coe ﬃ cient - measures the level of con f dence (the probability) that the C.I. will enclose the parameter we estimate....
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This note was uploaded on 01/06/2011 for the course ISOM 111 taught by Professor Hu,inchi during the Fall '10 term at HKUST.
- Fall '10