(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Consider the distributions N(mu1, 400) and N(mu2, 225). Let theta = mu1-mu2 and x and y be the observed means of two independent random samples, each of size n, from these two disbtibutions. We reject H(0) : theta = 0 and accept H(a): theta >0 if and only if x-y >=C. If pi(theta) is the power function of this test, find n and C so that pi(theta=10) = 0.95 at significance level alpha = 0.05.

Thank for anyone's help.

3. The attempt at a solution

[tex]

{X-Y-10\over\sqrt{{400\over n}+{225\over n}}}=-1.645

[/tex]

and:

[tex]C = X-Y=1.645\sqrt{{400\over n}+{225\over n}}[/tex]

So if I subtract the first equation from the 2nd, I get:

[tex]10=3.29\sqrt{{400\over n}+{225\over n}}[/tex]

and n = 67.65, but since it should be a whole number, we round up to 68?

Is any of this right, or what's the correct answer?

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# Homework Help: Please help with simple statistics problem

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