Question

1. visualizing fuel efficiency the dotplot shows the difference (highway - city) in epa mileage ratings for each of the 21 model year 2014 midsize cars.

a. the dot above - 3 is for the toyota prius. explain what this dot represents.

b. what percent of these car models get fuel efficiency of at least 10 mpg more on the highway than in the city?

Explanation:

Step1: Analyze the dot - plot concept

A dot - plot shows the distribution of a variable. Here, the variable is (Highway - City) fuel efficiency. Each dot represents a car model.

Step2: Interpret the dot for part (a)

The dot above - 3 for the Toyota Prius means that for the Toyota Prius, the difference (Highway - City) in EPA mileage ratings is - 3. In other words, the city mileage rating of the Toyota Prius is 3 mpg higher than its highway mileage rating.

Step3: Count the number of cars for part (b)

We need to find the number of cars with (Highway - City) $\geq10$. Count the dots at 10, 11, 12. Let's assume from the dot - plot (since the exact counts of dots at 10, 11, 12 are not given in text but we know the total number of cars $n = 21$). Suppose the number of cars with (Highway - City) $\geq10$ is $x$. The formula for percentage is $P=\frac{x}{n}\times100$.

Answer:

a. The dot above - 3 for the Toyota Prius means that the city mileage rating of the Toyota Prius is 3 mpg higher than its highway mileage rating.
b. Suppose the number of cars with (Highway - City) $\geq10$ is $x$. The percentage is $P = \frac{x}{21}\times100$. (If, for example, $x = 3$ from a typical dot - plot interpretation, then $P=\frac{3}{21}\times100=\frac{100}{7}\approx14.29\%$)