Question

Speedy net service is concerned that the level of access for customers is decreasing, as a result of heavier use. The proportion of peak period time when a customer’s download speed drops by 20 percent or more below average time is considered a good measure of service level. The percentage of time a customer experiences such drops during peak periods varies. Using a sampling process, the ISP set up control charts to monitor the service level, based on proportion of below average download speed during peak periods. Construct the p-chart using the sample data in the table worksheet Prob 07-07 in the ch07data.xlsx file on the student companion site for this chapter. What does the chart show? Is the service level based on the pchart data good or bad in your opinion?

Peak	Number of	Number of
Period	Calls Attempted	Busy Signals
1	492	8
2	424	9
3	508	4
4	614	5
5	566	11
6	616	6
7	528	5
8	382	8
9	608	8
10	506	5
11	596	3
12	510	9
13	428	11
14	524	8
15	410	3
16	586	9
17	488	8
18	618	3
19	552	9
20	466	10
21	472	6
22	484	2
23	468	8
24	574	8
25	606	7
26	620	7
27	575	5
28	600	8
29	541	5
30	393	4

Answer 1