Variations in the production process that can be traced to specific causes.

A quality control chart that is used to control the number of defects per unit of output.

The theoretical foundation for $\overline{x}$- charts. It states that, regardless of the distribution of the population of all parts or services, the distribution of $\overline{x}$s will tend to follow a normal curve as the sample size grows.

A graphic presentation of process data over time.

Variabilities that affect almost every production process to some degree and are to be expected; also known as common causes.

A quality control chart that is used to control the percentage of defects.

The degree to which a product or service meets the specifications set for it.

A process control chart that tracks the range within a sample; indicates that a gain or loss of uniformity has occurred in a production process.

An emphasis on quality that encompasses the entire organization.

A quality control chart for variables that indicates when changes occur in the central tendency of a production process.