Question

You are given e=0.020 a confidence level of 90% and a sample portion of 85% from a recent survey find the minimum sample size to estimate a population proportiona.1225b.259c.5751d.863

Answer 1

The answer you are looking for is D.863

Answer 2

Option d)863

Explanation:

Given that

e=Margin of error = 0.020

Confidence level =90%

zcritical for 90% =1.645

We have margin of error = 1.645 (std dev)/sq rt n

where n = sample size

Since p = 0.85

Std error =
`\sqrt[2]{(pq)/(n) } =\sqrt[2]{(0.85(0.15))/(n) } \\=\frac{0.357}{\sqrt[2]{n} }`

Substitute in margin of error to get

0.020=1.645(0.357)/sqrt n

Simplify to get

n=862.54

Since n cannot be in decimal round off to the next integer

n =863