In a sample of 400 voters, 360 indicated they favor the incumbent governor. The 95% confidence interval of voters not favoring the incumbent is
A)0.871 to 0.929
B)0.120 to 0.280
C)0.765 to 0.835
D)0.071 to 0.129

Question

Quizplus · Accepted Answer

The proportion of voters not favoring the incumbent is 40/400 = 0.1. Using the formula for a confidence interval for a proportion, the 95% confidence interval is approximately 0.071 to 0.129.

In a Sample of 400 Voters, 360 Indicated They Favor