A set of data from a process has 8 readings per sample and 50 samples. The mean of the 50 sample means is 12.62. The mean of the 50 ranges is 0.18.Find the control limits for a median chart.
Here is a partial ANOVA table. Use = 0.05.
The values of x, y and z should be:
An x-bar and R chart is used to monitor a process. One week ago a new type of raw material was introduced and since that time 60 points have been plotted on the xbar chart and all are in the middle third of the chart. The corresponding 60 points on the R chart are all below the average range. This indicates that:
The average number of defects is 21.6. Find the upper control limit for the c-chart.
An indication of the experimental error is available because the design has: