College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 80 messages that were not business related. The 95% confidence interval for the population proportion is:
A) 0.167 to 0.233
B) 0.161 to 0.239
C) 0.148 to 0.252
D) 0.186 to 0.254
E) 0.179 to 0.261

Question

Quizplus · Accepted Answer

The sample proportion is 80/400 = 0.20. Using the formula for a confidence interval for a proportion, the 95% confidence interval is calculated as 0.20 ± 1.96 * sqrt((0.20*(1-0.20))/400), which results in the interval 0.161 to 0.239.

College X Is Concerned About Their Employees Making Use of Their