The population standard deviation for the scores of a standardized test is 5

points. If we want to be 95%

confident that the sample mean is within 2

points of the true population mean, what is the minimum sample size that should be taken?

z

0.10

1.282

z

0.05

1.645

z

0.025

1.960

z

0.01

2.326

z

0.005

2.576

Use the table above for the z

-score, and be sure to round up to the nearest integer.