We've been developing intuitive high-quality statistical software at an affordable price, backed up by fast friendly customer service for over 25 years...
Office hours: 9am-5pm GMT Mon-Fri
It's Tuesday 5:02 PM and the office is closed - e-mail us and we'll get back to you as soon as possible.
Attributes control charts plot quality characteristics that are not numerical (for example, the number of defective units, or the number of scratches on a painted panel).
It is sometimes necessary to simply classify each unit as either conforming or not conforming when a numerical measurement of a quality characteristic is not possible. In other cases, it is convenient to count the number of nonconformities rather than the number of nonconforming units. A unit may have a number of nonconformities without classing the unit as nonconforming. For example, a scratch on a painted panel may be a nonconformity but only if several such scratches exist would the
entire panel be classed as a nonconforming unit.