- #1

kingwinner

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## Homework Statement

http://www.geocities.com/asdfasdf23135/stat14.JPG

## Homework Equations

Statistics: power function

## The Attempt at a Solution

a) Test statistic: Z = (X bar - 13) / (4/sqrt n)

Let μ = μ_a > 13 be a particular value in H_a

Power(μ_a)

= 1- beta(μ_a)

= P(reject Ho | H_a is true)

= P(reject Ho | μ = μ_a)

= P(Z>1.645 | μ = μ_a)

= P(X bar > 13 + [(1.645 x 4)/(sqrt n)] | μ = μ_a)

I also know that X bar ~ N(μ, 16/n)

I am stuck here...How can I proceed from here and express the power in terms of μ and n?

Thank you very much!

[note: also discussing in other forum]