The file McDonalds Stores contains the number of McDonald's stores per 100,000 population located in each of the 50 U.S. states as of September 13, 2018.
a. Calculate the mean, variance, and standard deviation for this population.
b. What percentage of the 50 states have a number of McDonald's stores within ± 1, ± 2, or ± 3 standard deviations of the mean?
c. Compare your findings with what would be expected on the basis of the empirical rule. Are you surprised at the results in (b)?