Use both formula and probability distributions to answer each question. Then use a function in your calculator to check your answer. Make sure you always write down what you entered into your calculator.

Question 5

In a study of the effect of air pollution on lung function, a sample of 50 chil- dren living in a community with a high level of ozone pollution had their lung capacities measured, and 14 of them had capacities that were below normal for their size. A second sample of 80 children was drawn from a community with a low level of ozone pollution, and 12 of them had lung capacities that were below normal for their size. Construct a 95% confidence interval for the difference between the proportions of children with lung capacities below normal in the two communities.