A bank offers auto loans to qualified customers. The amount of the loansare normally distributed and have a known population standard deviation of4

thousand dollars and an unknown population mean. A random sample of22

loans is taken and gives a sample mean of42

thousand dollars.

Find themargin of errorfor the confidence interval for the population mean with a90%

confidence level.

z

0.10

z

0.10

z

0.05

z

0.05

z

0.025

z

0.025

z

0.01

z

0.01

z

0.005

z

0.005

1.282

1.645

1.960

2.326

2.576

You may use a calculator or the commonz

values above.

• Use4
• for the population standard deviation and42
• for the sample mean. Round the final answer to twodecimal places.