# 409Quiz2ans - Let μ = this year’s overall mean SAT...

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STAT 409 Fall 2009 Name ANSWERS . Quiz 2 (3 points) Be sure to show all your work, your partial credit might depend on it. No credit will be given without supporting work. 1. At Anytown State University, the population standard deviation of the SAT scores of entering students is 72. Last year’s overall mean SAT score of entering students was 1100. We suspect that this year’s overall mean SAT score is higher. Find the power of the appropriate test at μ = 1111, if the decision is be based on a random sample of 81 students from this year's class, and a 5% level of significance is used.

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Unformatted text preview: Let μ = this year’s overall mean SAT score. Claim: μ > 1100. H : μ ≤ 1100 vs. H 1 : μ > 1100 . Right – tailed. Rejection Region : Reject H if Z = n σ μ X-> z α ⇒ Z = 81 72 1100 X-> 1.645 ⇒ 81 72 645 . 1 1100 X ⋅ + = 1113.16 . Power ( μ = 1111 ) = P ( Reject H | H is NOT true ) = P ( X > 1113.16 | μ = 1111 ) = -81 72 1111 16 . 1113 Z P = P ( Z > 0.27 ) = 1 – Φ ( 0.27 ) = 1 – 0.6064 = 0.3936 ....
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## This note was uploaded on 10/12/2011 for the course STATISTICS stat 410 taught by Professor Stepanov during the Spring '11 term at University of Illinois, Urbana Champaign.

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409Quiz2ans - Let μ = this year’s overall mean SAT...

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