Term
| Statistical process control (SPC) |
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Definition
| A process used to monitor standards by taking measurements and corrective action as a product or service is being produced. |
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Definition
| A graphical presentation of process data over time. |
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Definition
| Variability that affects every production process to some degree and is to be expected; also known as common cause. |
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Definition
| Variation in a production process that can be traced to specific causes. |
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Definition
| A quality control chart for variables that indicates when changes occur in the central tendency of a production process |
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Definition
| A control chart that tracks the "range" within a sample; it indicates that a gain or loss in uniformity has occurred in dispersion of a production process |
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Term
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Definition
| The theoretical foundation for x-charts, which states that regardless of the distribution of the population of all parts or services, the distribution of xs tends to follow a normal curve as the number of samples increases. |
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Definition
| A quality control chart that is used to control attributes. |
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Definition
| A quality control chart used to control the number of defects per unit of output. |
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Definition
| A test used to examine the points in a control chart to see if nonrandom variation is present. |
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Definition
| The ability to meet design specifications. |
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Term
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Definition
| A ratio for determining whether a process meets design specifications; a ratio of the specification to the process variation. |
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Term
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Definition
| A proportion of variation (3o)between the center of the process and the nearest specification limit. |
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Term
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Definition
| A method of measuring random samples of lots or batches of products against predetermined standards. |
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Term
| Operating characteristic (OC) curve |
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Definition
| A graph that describes how well an acceptance plan discriminates between good and bad lots. |
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Term
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Definition
| The mistake of having a producer's good lot rejected through sampling. |
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Term
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Definition
| The mistake of a customer's acceptance of a bad lot overlooked through sampling. |
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Term
| Acceptable quality level (AQL) |
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Definition
| The quality of a lot considered good. |
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Term
| Lot tolerance percentage defective (LTPD) |
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Definition
| The quality level of a lot considered bad. |
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Term
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Definition
| Statistically, the probability of rejecting a good lot. |
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Term
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Definition
| Statistically, the probability of accepting a bad lot. |
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Term
| Average outgoing quality (AOQ) |
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Definition
| The percentage defective in an average lot of goods inspected through acceptance sampling. |
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