dolution

 EPA mpg 2013. In 2008, the EPA revised their methods for estimating the fuel efficiency (mpg) of cars—a factor that plays an increasingly important role in car sales. How do the new highway and city estimated mpg values relate to each other? Here’s a scatterplot for 76 family sedans as reported by the U.S. government. These are the same cars as in Exercise 41.  

(a) The correlation of these two variables is 0.896. Describe the association.

(b) If the hybrids were removed from the data, what would you expect to happen to the slope (increase, decrease, or stay pretty much the same) and to the correlation (increase, decrease, the same)? Try it using technology. Report and discuss what you find.