Carmen Homework 3 - Descriptive Statistics

Data are collected on the fuel economy of 2016 model midsize cars. The information measured in average miles per gallon (mpg) is summarized below: The government is interested in cars using less fuel, so they decide to provide a 'gas saver tax credit' for those who own vehicles that get a good gas mileage. What is smallest value for MPG if you want only 25% of the cars to receive this tax incentive?

33.750 mpg

Match the boxplots below to their Five Number Summaries: Min Q1 Median Q3 Max #1 10 12 20 22 30 #2 10 18 20 28 30 #3 10 15 20 25 30

Boxplot C1 goes with Five Number Summary #2, C2 with #1, and C3 with #3.

Outliers significantly affect the value of the median.

False

Boxplot A and Boxplot B are drawn on the same axes. If Boxplot A is shorter in length than boxplot B, it also has to contain less data than Boxplot B.

False

Speeds were recorded by a police officer in a speed trap and summarized in the boxplot shown. Which of the following statements is true about the data?

Half the drivers were driving between about 70 and about 80 miles per hour.

Which of the following summary measures can be directly calculated from a boxplot?

IQR

If a data set is skewed to the left, how will the mean and median compare?

The mean will be less than the median.

A taxi cab company takes a random sample of 50 of its taxis and notes their miles per gallon (mpg) on a test run. The computer output is shown below. From this output we can find the value of the interquartile range.

True

In thinking about the 5-number summary, the percentage of data below Q1 and above Q3 combined is the same as the percentage of data in the IQR.

True

Suppose your data represent revenues from a group of 20 stores in a retail chain across the country, and revenue is measured in millions of dollars. The first quartile of this data set would also be measured in millions of dollars.

True