Answer:
Option d)863
Step-by-step 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 = [tex]\sqrt[2]{\frac{pq}{n} } =\sqrt[2]{\frac{0.85(0.15)}{n} } \\=\frac{0.357}{\sqrt[2]{n} }[/tex]
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
