Sankhya: The Indian Journal of Statistics

1994, Volume 56, Series A, Pt. 3 , pp. 545-549

ANALYSIS OF PROCESS CONTROL FOR PROPORTION WASTAGE

By

RATAN DASGUPTA, Indian Statistical Institute

SUMMARY. Usually $p$-charts have been used for process control analysis of fraction defective under binomial model. However when we consider proportions like $p = X/Y$, where $X$ = length (or area or quantity or value) wasted and $Y$ = length (or area or quantity or value) produced, $p$-chart treatment is not strictly valid. A regression based approach is proposed in this paper to study process control of `$p$'. The advantage with this method is that the criterion is independent of unit of measurement of $Y$, unlike in `$p$' - chart with limits as : $p' \pm 3(p'q' /Y)^{1/2}$.

AMS (1991) subject classification. Primary 62A99; secondary 62N10.

Key words and phrases. $p$-chart, fraction defective, proportion wastage.

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This paper in Mathematical Reviews.