KPBS is interested in estimating the mean number of minutes per day that children spend watching TV. The population standard deviation is KNOWN to be 21.5 minutes. KPBS selected a random sample of n = 200 children and found that the average time watched by children was 191.3 minutes.

To develop a 95% confidence interval estimate, what is the z CRITICAL VALUE? You may use Appendix F or Excel.

1.96

1.28

1.645

2.575

Using the KPBS scenario above to develop a 95% confidence interval estimate, what is the MARGIN OF ERROR?

1.52 minutes

2.98 minutes

42.14 minutes

2.50 minutes