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Process capability

I NEED GUIDELINES.

1. Prepare a means-ranges chart using the five journeys on each day as a sample. Find the control limits and state your inferences from this chart.
2. Prepare a 5-point moving-means-ranges chart. Again find the control limits and state your inferences. Describe your inferences in comparison with those from part (1) and explain the advantages and drawbacks of the two kinds of analysis.
3. The airline's legal affairs manager is concerned that this approach will encourage the bus operator to pressurise drivers into driving too quickly in order to keep a high average. She has therefore asked for a control chart that shows how often the average speed has exceeded the proposed upper limit for contractual performance. Prepare an appropriate attributes chart that shows how often, on each day, average speed is excessive according to this definition. State your inferences from this chart.
4. The legal affairs manager has decided that the sample for this control chart should not be the first five journeys on each day, since some samples include journeys made by more than driver. You are now therefore asked to prepare an appropriate attributes chart such that each sample consists of the journeys of each driver. Thus, for example, the first sample is the series of journeys driven by the first driver shown in Exhibit 1. Again state your inferences.
5. Prepare an analysis of process capability, based on the proposed contractual journey speed limits, applying 1) the usual 3-standard deviation convention, 2) the acceptable failure rate that is proposed for the contract. For item (2) you will need to work out how many standard deviations of a normal distribution enclose the appropriate proportion of the population. State your inferences.

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Process Capability

Till this point, we have evaluated the current processes to see whether the variability for the processes is within statistical control. However, we have not evaluated whether these are within the specification limit or not. In this section, we evaluate the process capability. Process capability measures how close a process is running to its specification ...

Solution Summary

This post shows how to manage risk through a comprehensive case study. It specifically show how to prepare a means-ranges chart, prepare a 5-point moving-means-ranges chart, prepare attributes chart, and prepare an analysis of process capability.

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