Q 40. - The Practice of Statistics for AP

Question

Fuel efficiency In an earlier example, we examined data on highway gas mileages of the model year $2009$ midsize cars. The dot plot below shows the difference (highway – city) in EPA mileage ratings for each of the $24$car models from the earlier example. 

(a) Explain what the dot above $6$represents.

(b) What does the graph tell us about fuel economy in the city versus on the highway for these car models? Be specific. 

Step-by-Step Solution

Answer

Part (a) The dot above $6$ denotes that one of $21$ automobile models had EPA mileage that was higher on the highway than in the city.

Part (b) In comparison to the city, the highway has a higher EPA mileage 

Step 1: Given information

Given graph : 

Part (a) Step 2: Concept

Dot-plots in the figure indicates the distance between highway and city that are presented as mileage.  

Part (a) Step 3: Explanation

The dot-plot shows the difference in EPA mileage ratings (highway-city) for each of the $21$ car models. The dot above $6$ indicates that one of $21$ automobile models had EPA mileage that was $6$ points greater on the highway than in the city.

Part (b) Step 1: Explanation

In comparison to the city, the highway has a higher EPA mileage. On the highway, fuel economy is better than in the city.