In 2000, a growing number of warranty claims on Firestone tires sold on Ford SUVs prompted Firestone and Ford to issue a major recall. An analysis of warranty claims data helped identify which models to recall. A breakdown of 2,504 warranty claims based on tire size is given in the following table:
Tire Size Number of Warranty Claims
23575R15..............................2,030
311050R15...............................137
30950R15.................................82
23570R16.................................81
331250R15................................58
25570R16.................................54
Others......................................62
The 2,030 warranty claims for the 23575R15 tires can be categorized into ATX models and Wilderness models. The type of incident leading to a warranty claim, by model type, is summarized in the following table:

a. Construct a Pareto chart for the number of warranty claims by tire size. What tire size accounts for most of the claims?
b. Construct a pie chart to display the percentage of the total number of warranty claims for the 23575R15 tires that come from the ATX model and Wilderness model. Interpret the chart.
c. Construct a Pareto chart for the type of incident causing the warranty claim for the ATX model. Does a certain type of incident account for most of the claims?
d. Construct a Pareto chart for the type of incident causing the warranty claim for the Wilderness model. Does a certain type of incident account for most of the claims?

Transcribed Image Text:

ATX Model Warranty Claims Wilderness Warranty Claims Incident Type Tread separation Blowout Other/ 59 41 1,365 unknown Total 422 1.864 166