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!!!! : )