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XCHART Statement |

The following notation is used in this chapter:

denotes the mean of the population, also referred to as the
process mean or the process level. | |

denotes the target mean (goal) for the population.
Goel and Wu (1971) refer to as the
"acceptable quality level" and use the symbol
instead. The symbol is
used for in Glossary and Tables for
Statistical Quality Control. You can provide with the MU0= option or with the variable _MU0_
in a LIMITS= data set. | |

denotes the population standard deviation.
You can provide with the variable
_STDDEV_ in a LIMITS= data set (where
_TYPE_=STANDARD). | |

denotes a known standard deviation. You can provide with the SIGMA0= option or the variable _STDDEV_ in a LIMITS= data set. | |

denotes an
estimate of . You can provide with
the SIGMA0= option or the
variable _STDDEV_ in a LIMITS= data set. To identify this
value as an estimate, specify TYPE=ESTIMATE
or assign the value ESTIMATE to the variable _TYPE_ in a
LIMITS= data set. | |

n | denotes the nominal sample size for the cusum scheme.
You can provide n with the LIMITN= option or the
variable _LIMITN_ in a LIMITS= data set. |

denotes the shift in to be detected, expressed as a multiple of the standard deviation. You can provide with the DELTA= option or the variable _DELTA_ in a LIMITS= data set. | |

denotes the shift in to be detected, expressed
in data units. If the sample size n is constant
across subgroups, then . | |

Some authors use the symbol D instead of ;for example, refer to Johnson and Leone (1962, 1974) and Wadsworth and others (1986). You can provide with the SHIFT= option. Although it may be more natural to specify the shift in data units, it is preferable to specify the shift as , since this generalizes to data with unequal subgroup sample sizes. |

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