Upper Tolerance Intervals Adjusted for Multiple Nuisance Uncertainties

• Autores: Greg F. Piepel, Scott K. Cooley, Matthew R. Paul
• Localización: Journal of quality technology: A quarterly journal of methods applications and related topics, ISSN 0022-4065, Vol. 40, Nº. 3, 2008, págs. 245-258
• Idioma: inglés
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• Resumen

  • In many product-quality situations, it must be shown with high confidence (X%) that a high percentage (at least Y%) of the product made during the production period has true values of property below a calculated value. This can be done using an X%/Y% upper tolerance interval (X%/Y% UTI). This article discusses a methodology and formulas for calculating X%/Y% UTIs on the true property values when there are sources of uncertainty from nuisance uncertainties in addition to the source of variation of interest. The nuisance uncertainties may include regression model uncertainty if a regression model is used. The proposed method is shown to achieve the nominal X% and Y% values and yields smaller UTIs than not adjusting for the nuisance uncertainties.