Suppose pages per book in a library are normally distributed and have a known population standard deviation of22

pages and an unknown population mean. A random sample of21

books is taken and gives a sample mean of265

pages. Find the error bound (EBM) of the confidence interval with a95%

confidence level.

z

0.10

z

0.05

z

0.025

z

0.01

z

0.005

1.282

1.645

1.960

2.326

2.576

Select the correct answer below:

6.155

7.897

9.410

11.167

12.367

12.959