Question

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c. What sample size is needed so that the length of the interval is $60 with 95% confidence?

Answer 1

What sample size is needed so that the length of the interval is $60 with 95% confidence? We Assume: σ = $150.

Showing Work:

n ======> is the sample size we want to find:

N = ( z a/2^σ / E )^2

= ( 1.96 * 150 / 30 )^2 (margin of error is 1.96 times the standard error):

Answer: =======> 96.04 ≈ 97

Hope that helps!!!! : )