Question

A poll of 2,237 likely voters was conducted on the president’s performance. Approximately what margin of error would the approval rating estimate have if the confidence level is 95%?

Answer 1

Solution:

Given that ,

n = 2237

c = 95% = 0.95

Find the margin of the error for the estimating the population proportion.

The margin of the error E is given by

E =  

Here , no prior information of p is given.

In this case, take p = 0.5

1 - p = 1 - 0.5 = 0.5

Now, = 1 - c = 1 - 0.95 = 0.05

/2 = 0.05/2 = 0.025

= 1.96

  E =  

= 0.02072015899