Sess. 4-1 Trend Control of a Group of Multiple Failure Rates, which has Between and Within Lots Variation

Abstract

It is not effective to use a usually applied p-control chart when the variation between and within groups of multiple failure rates is large. For such a case, we present a new method of controlling failure rates properly by using logit transformation and inverse sine transformation so as to transform an attribute value to a measurable value and by applying an x - Rs control chart and an x^^--S control chart to a measurable value.