Question

The latest poll of 400 randomly selected residents showed that 288 of them are hoping that the old town cinema stays open on Main Street.

With a desired confidence interval of 95%, which has a z*-score of 1.96, what is the approximate margin of error for this polling question?

A) 4%
B) 5%
C) 7%
D) 8%

Answer 1

A

Explanation:

Answer 2

The approximate margin of error is 4%.

Using the formula given and our information, we have:


`E=1.96* \sqrt{((288)/(400)(1-(288)/(400)))/(400)} \\ \\=1.96* \sqrt{(0.72(1-0.72))/(400)}=1.96* \sqrt{(0.72(0.28))/(400)} \\ \\=0.044\approx 0.04=4%`