Question

A Gallup survey conducted April 2–11, 2018, found that 152 out of 1015 American adults mentioned immigration/illegal aliens as the most important problem facing the nation. An earlier survey conducted in February 2011 found that 108 out of 978 American adults mentioned immigration/illegal aliens as the most important problem facing the nation.

Construct a 99% confidence interval for the change in the proportion of American adults who mentioned immigration /illegal aliens as the most important problem facing the nation. Round your answer to three decimal places. Use subscript 1 for the year of 2018 and 2 for the year of 2011.

Answer 1

2018 (Data 1)

x1 = 152

n1= 1015

= x1/ n1 = 152/ 1015 = 0.150

2011 (Data 2)

x2 = 108

n2= 978

= x2/ n2 = 108 / 978 = 0.110

z value for 99% CI = 2.576

Confidence interval :  

CI = 0.001 0.078

ANS : Confidence interval (0.001 , 0.078)