Question: In summer 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 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:

Incident ATX Model Warranty Claims Wilderness Warranty Claims

Tread separation 1,365 59

Blowout 77 41

Other/unknown 422 66

Total 1,864 166

a. Construct a Pareto diagram 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 diagram for the type of incident causing the warranty claims