Question

In a​ poll, 69​% of the people polled answered yes to the question​ "Are you in favor of the death penalty for a person convicted of​ murder?" The margin of error in the poll was 5​%, and the estimate was made with 96​% confidence. At least how many people were​ surveyed?

The minimum number of surveyed people was___

Answer 1

Solution :

Given that,

= 0.69

1 - = 1 - 0.69 = 0.31

margin of error = E = 5% = 0.05

At 96% confidence level the z is ,

Z/2 =2.054 ( Using z table )

Sample size = n = (Z/2 / E)2 * * (1 - )

= (2.054 / 0.05)2 * 0.69 * 0.31

= 360.97

Sample size =361