Assume that a random sample is used to estimate a population

Assume that a random sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level n = 600, x =120, 90% confidence The margin of error E = (Round to four decimal places as needed.)

Solution

N=600

x=120

z for 90% confidence level = 1.645

Proportion p = 120/600 = 0.2

Margin of Error E = z * sqrt(p(1-p)/N)

= 1.645 * sqrt(0.2*(1-0.2)/600)

= 0.0269 Answer