Each day 500 inventory control records checked for correctness. The table below show the number of defective records each day for a 20-day period.

a) Calculate the centerline and control limits for a p chart.

b) Create the control chart

c) Is the process stable?

Day Number of Records Sampled Number of Defective Records 500 N 500 4 W 500 2 500 8 UT 500 6 500 5 500 500 9 500 9 10 500 10 11 500 8 12 500 W 13 500 8 14 500 6 15 500 4 16 500 7 17 500 12 18 500 6 19 500 4 20 500 5