Elwin Osbourne, CIO at GFS, Inc., is studying employee use of GFS e-mail for non-business communications.A random sample of 200 e-mail messages was selected.Thirty of the messages were not business related.The 95% confidence interval for the population proportion is _________.
A)0.108 to 0.192
B)0.153 to 0.247
C)0.091 to 0.209
D)0.101 to 0.199
E)0.199 to 0.201

Question

Quizplus · Accepted Answer

The sample proportion is 30/200 = 0.15. Using the formula for a confidence interval for a proportion, the interval is calculated as 0.15 ± 1.96 * sqrt((0.15*(1-0.15))/200), which results in approximately 0.101 to 0.199.