The Franklin Tire Company is interested in demonstrating the durability of its steel-belted radial tires. To do this, the managers have decided to put four tires on 100 different sport utility vehicles and drive them throughout Alaska. The data collected indicate the number of miles (rounded to the nearest 1,000 miles) that each of the SUVs traveled before one of the tires on the vehicle did not meet minimum federal standards for tread thickness. The data file is called Franklin.

a. Construct a frequency distribution and histogram using eight classes. Use 51 as the lower limit of the first class.

b. The marketing department wishes to know the tread life of at least 50% of the tires, the 10% that had the longest tread life, and the longest tread life of these tires. Provide this information to the marketing department. Also provide any other significant items that point out the desirability of this line of steel-belted tires.

c. Construct a frequency distribution and histogram using 12 classes, using 51 as the lower limit of the first class. Compare your results with those in parts a and b. Which distribution gives the best information about the desirability of this line of steel-belted tires? Discuss.