The data set above was also used to answer these additional research questions:
a.Was the average household size in 1960 equal to 3.67, as claimed by the website Statistica.com?
b.Was there a difference between average death rates in metropolitan areas with low and high nitrous oxide potential in 1960?
c.Was there a change in mean July (maximum) temperatures between the data collections in 1960 and 2000? Use an appropriate 95% confidence interval to answer this question.