A manufacturing process produces 500 parts per hour One samp

A manufacturing process produces 500 parts per hour. One sample part is taken every half-hour and after five parts are obtained, the average of these five measurements is plotted on an xbar control chart.

a. Is this an appropriate sampling scheme if an assignable cause results in an instantaneous shift of the process upward for about a 10 minute period? Explain.

b. Is there a better alternative for the sampling scheme? If so, describe it

Solution

a.

This is not an appropriate sampling scheme for the given scenario,since every data point recorded for the variable is for a minimum period of a 30*5= 150 minutes or 2.5 hours. if its shows some spike change for about 10 minute period the spike is not necesarily reasonable.

b.

Yes There is a better sampling scheme. It can be done by taking the moving average of the data.