To construct a p-chart, 20 samples of size 150 were drawn from a process. The proportion of

Question:

To construct a p-chart, 20 samples of size 150 were drawn from a process. The proportion of defective items found in each of the samples is listed in the next table.

Proportion Defective Proportion Defective Sample Sample 1 2 3 4 5 .03 .05 .10 .02 .08 .09 11 12 13 14 .07 .04 .06 .05 .0

a. Calculate and plot the centerline and the upper and lower control limits for the p-chart.
b. Calculate and plot the A, B, and C zone boundaries on the p-chart.
c. Plot the sample proportions on the p-chart.
d. Is the process under control? Explain.
e. Should the control limits and centerline of part a be used to monitor future process output? Explain.