Janice Sanders, CEO of Pine Crest Medical Clinic, is concerned over the number of times patients must wait more than 30 minutes beyond their scheduled appointments. She asked her assistant to take random samples of 64 patients to see how many in each sample had to wait more than 30 minutes. Each instance is considered a defect in the clinic process. The table below contains the data for 15 samples.
Sample Number of Defects
1 ............5
2 ............2
3 ............1
4 ............3
5 ............1
6 ............5
7 ............2
8 ............3
9 ............6
10 .............3
11 .............9
12 .............9
13 .............5
14 .............2
15 .............3
a. Assuming Janice Sanders is willing to use three-sigma control limits, construct a p-chart.
b. Based on your p-chart and the data in the table, what can you conclude about the waiting time of the patients?