Introduction

I have created an evaluation of a manufacturing process test-run based on control charts that I have generated from the given data. I have been given three days’ worth of data. The process was allowed to run for 23 hours each day without interruption, other than the regular end-of-day maintenance during the last hour. I have examined the control charts and have identified the hour at which the process should have been shut down. I have cited the Nelson’s law to support my decision. For this evaluation, historically the process mean is 25, the standard deviation is 1.75, the sample size per hour is 5, the standard deviation of the sample mean is 0.783, the Upper Control Limit is 27.35, and the Lower Control Limit is 22.65.

Day One

As you can see in the control chart for day on, there is a clear violation of Nelson’s third rule at hour nine and production should have been halted there as it was the fourth sample mean farther than one standard deviation away from the mean

Day Two

As you can see in the control chart for day two, there is a clear violation of Nelson’s second rule at hour four and production should have been halted there because it was the second of three points to be consecutively farther than two standard deviations away from the mean.

Day Three

As you can see in the control chart for day three, there are no violations so there is no need to halt production.

Works Cited

All the information about Nelson’s law came from the attached website. https://ximera.osu.edu/qcstats/QC_stats/STAT_QC-0250/main