Description Usage Arguments Rules list Source

These rules are used for quality control (QC). Default values are set for Nelson's criteria, but they also support Westgard, AIAG, Montgomery and Healthcare QC rules.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | ```
rule1(x, m = mean(x), s = sd(x))
rule2(x, m = mean(x), min.run = 9)
rule3(x, min.run = 6)
rule4(x, m = mean(x), min.run = 14, direction.mean = FALSE)
rule5(x, m = mean(x), s = sd(x), min.run = 3)
rule6(x, m = mean(x), s = sd(x), min.run = 5)
rule7(x, m = mean(x), s = sd(x), min.run = 15)
rule8(x, m = mean(x), s = sd(x), min.run = 8)
``` |

`x` |
vector with values |

`m` |
mean |

`s` |
standard deviation |

`min.run` |
minimal amount of sequential values before rule is triggered (defaults to Nelson's) |

`direction.mean` |
a logical to indicate whether |

Nelson (N), Westgard (W), AIAG (A), Montgomery (M), Healthcare (H): | N | W | A | M | H |

--------------------------------------------------------------------------------------- | ----- | ----- | ----- | ----- | ----- |

#1 One point is more than 3 standard deviations from the mean. | 1 | 1 | 1 | 1 | 1 |

#2 n (or more) points in a row are on the same side of the mean | 9 | 9 | 7 | 8 | 8 |

#3 n (or more) points in a row are continually incr. or decr. | 6 | - | 6 | 6 | 6 |

#4 n (or more) points in a row alternate in direction, incr. then decr. | 14 | - | 14 | 14 | - |

#5 n - 1 out of n points in a row are >2 sd from the mean | 3 | 3 | 3 | 3 | 3 |

#6 n - 1 out of n points in a row are >1 sd from the mean | 5 | 5 | 5 | 5 | - |

#7 >= n points in a row are within 1 sd of the mean | 15 | - | 15 | 15 | 15 |

#8 >= n points in a row outside 1 sd of the mean, in both directions | 8 | - | 8 | 8 | - |

Nelson LS. **The Shewhart Control Chartâ€”Tests for Special Causes**. Journal of Quality Technology [Internet]. Informa UK Limited; 1984 Oct;16(4):237â€“9. Available from: http://dx.doi.org/10.1080/00224065.1984.11978921

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