College X is concerned about their employees making use of their email for non-business purposes. A random sample of 400 e-mails discovered 60 messages that were not business related. The 90%
Confidence interval for the population proportion is:
A) 0.104 to 0.196
B) 0.115 to 0.185
C) 0.148 to 0.252
D) 0.121 to 0.179
E) 0.186 to 0.254

Question

Quizplus · Accepted Answer

The formula for the confidence interval for a population proportion is:sample proportion +/- margin of errorwhere the margin of error is:z * sqrt((sample proportion * (1 - sample proportion)) / sample size)where z is the z-score corresponding to the desired confidence level.For a 90% confidence level, z = 1.645.Plugging in the values we have:0.15 +/- 1.645 * sqrt((0.15 * (1 - 0.15)) / 400)= 0.15 +/- 0.029= 0.121 to 0.179Therefore, the 90% confidence interval for the population proportion is 0.121 to 0.179.

College X Is Concerned About Their Employees Making Use of Their