Question

In a survey of 1020 adults, a polling agency asked"When you retire, do you think you will have enough money to live comfortably or not the 1020 surveyed, 539 stated that they were worried about having enough money to live comfortably in retirement. Construct a 99% confidence interval for the proportion of adults who are worried about having enough money to live confortably in retirement.

Answer 1

Solution :

Given that,

Point estimate = sample proportion = = x / n = 539 / 1020 = 0.528

1 - = 1 - 0.528 = 0.472

Z/2 = Z0.005 = 2.576

Margin of error = E = Z / 2 * (( * (1 - )) / n)

= 2.576 (((0.528 * 0.472) / 1020)

= 0.040

A 99% confidence interval for population proportion p is ,

± E

0.528 ± 0.040

(0.488 , 0.568)