3) A manufacturing plant for recreational vehicles receives shipments from three different parts vendors. There
has been a defect issue with some of the electrical wiring in the recreational vehicles manufactured at the plant.
The plant manager wonders if all of the vendors might be contributing equally to the defect issue. The plant
manager reviews a sample of quality assurance inspections from the last six months. The data are shown in the
table below.
Rejected
Perfect
Not perfect but acceptable
Purrfect Parts Co. Made 4-U Co. 25 Hour Parts Co.
53
93
22
48
71
31
70
88
282
Test an appropriate hypothesis to decide if the plant manager is correct. Give statistical evidence to support
your conclusion.