Background

A nonconformity is a quality characteristic that does not meet stipulated specifications. A nonconforming unit has one or more nonconformities such that the unit is unable to meet standards (or specifications) and is unable to function as required. For example, the specifications for the inside diameter of an axle might be 2?0.1 centimeters. This means that an axle with an inside diameter of 2.2 centimeters (or 1.8 centimeters) is defective.

Problem

A company has been working to decrease the proportion of defective items among those delivered to one of its major buyers. The specifications set by this purchaser for a certain quality characteristic are within 20.0?0.3 units. The following measurements have been reported for a sample of 50 items: