Render, Quantitative Analysis for Management, 12th Edition. 15-21. V.S. Industri
ID: 3154482 • Letter: R
Question
Render, Quantitative Analysis for Management, 12th Edition. 15-21. V.S. Industries in Parkersburg, West Virginia is a small manufacturer of military grade hybrid microcircuits. One of the many quality assurance procedures required by Military Standard 883J (MIL-STD-886J) for hybrid microcircuits is known as nondestructive bond pull (method number 2023.7 in MIL-STD-883J). The procedure involves pulling on a random sample of wires within the hybird microcicuit with a prespecified amount of force. If the wire tears, breaks, or sperates in any way from the circuit it fails the test and is considered defective and scrapped. In a recent batch of 1000 devoces 13 failed the pull test. Determine upper and lower control limits for the associated p-chart.
Explanation / Answer
Lower limit: p bar-3sqrt [pbar(1-pbar)/n],
and Upper limit: p bar+3sqrt [pbar(1-pbar)/n]
where pbar is proportion of devoces, failing the pull test, n is number of devoces.
13/1000-3sqrt [13/1000(1-13/1000)/1000] and 13/1000-3sqrt [13/1000(1-13/1000)/1000]
0.00225 and 0.02374