Several years ago, 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:

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?

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Number of Warranty Claims Tire Size 23575R15 311050R15 30950R 15 23570R16 331250R15 25570R16 Others 2.030 137 82 81 58 54 62 Source: Data extracted from Robert L. Simison, "Ford Steps Up Recall Without Firestone," The Wall Street Journal, August 14, 2000, p. A3. ATX Model Wilderness Warranty Claims 1.365 Warranty Claims Incident Type Tread separation Blowout Other/unknown Total 59 422 1.864 166 Source: Data extracted from Robert L. Simison, "Ford Steps Up Recall Without Firestone." The Wall Street Journal, August 14 2000, p. A3