The Ertl Company is well known for its high-quality die-cast metal alloy toy replicas of tractors and other farm equipment. As part of a periodic procurement evaluation, Ertl is considering purchasing parts for a toy tractor line from three different suppliers. The parts received from the suppliers are classified as having a minor defect, having a major defect, or being good.

Test results from samples of parts received from each of the three suppliers are shown below. Note that any test with these data is no longer a test of proportions for the three supplier populations because the categorical response variable has three outcomes: minor defect, major defect, and good.

Using the data above, conduct a hypothesis test to determine if the distribution of defects is the same for the three suppliers. Use the chi-square test calculations as presented in this section with the exception that a table with r rows and c columns results in a chi-square test statistic with (r – 1)(c – 1) degrees of freedom. Using a .05 level of significance, what is the p-value and what is your conclusion?

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Supplier Part Tested A В C Minor Defect 15 13 21 Major Defect 11 5 Good 130 126 124