In Exercises 89 and 90, we bring together all the measures of spread we have learned in the chapter and the new ones we learned in the exercises.

Question 3.202

89. Fuel Economy Data. You calculated the range, variance, and standard deviation for this data in Exercises 63–65. You calculated the coefficient of variation in Exercise 82 and the mean absolute deviation in Exercise 84. Use this information to do the following.

  1. Construct a table of the five measures of dispersion (range, sample variance, sample standard deviation, coefficient of variation, and mean absolute deviation) for the number of cylinders, the engine size, and the city mpg.

    148

  2. Which measures of dispersion suggest that the city mpg is the most dispersed variable? Engine size? Number of cylinders?

3.2.89

(a)

Range Sample
variance		 Sample
standard
deviation		 Coefficient
of variation		 Mean
absolute
deviation
Cylinders 8 9.6 3.098 51.64% 2
Engine size 4.9 3.078 1.754 52.89% 1.189
City mpg 30 116 10.770 44.88% 8.333

(b) City mpg: Range, Sample variance, Sample standard deviation, Mean absolute deviation. Engine size: Coefficient of variation; Cylinders: None of them.