Carbon footprint. Here are data relating the carbon footprint (tons of CO2 per year) to the new Environmental Protection Agency (EPA) highway mileage for 82 family sedans as reported by the U.S. government

(www.fueleconomy.gov/feg/byclass.htm). The car with the highest highway mpg and lowest carbon footprint is the Toyota Prius.

a) Would Spearman’s rho be an appropriate summary of the strength of the association shown here?

b) Find rho for the full data and for the relationship with the Prius removed. Comment.