Question

John Bruno owns a factory producing electric cords. John observes that recently the number of cords with defect has increased. He monitors the 3 processing machines for 30 days for 100 cords per observation per machine. The results of John Bruno’s observations are presented in the table below. What can he do to make sure that the number of cords with defect to go down?

Date	Number of Rejects by Cause
	Number of observations	Machine	Bad Wind	Twisted cord	Broken Leads	Abraded cord	Broken cord	Wrong wire	Failed Electrical Test
1	100	1	0	1	3	1	0	0	1
	100	2	2	1	0	0	2	5	0
	100	3	0	0	0	5	0	0	3
2	100	1	1	0	4	0	0	0	0
	100	2	3	1	0	0	1	3	0
	100	3	0	0	1	6	0	0	0
3	100	1	1	0	0	2	0	0	0
	100	2	0	0	0	0	0	3	0
	100	3	0	0	1	4	0	0	3
4	100	1	0	0	3	0	0	0	0
	100	2	0	0	0	0	0	2	0
	100	3	0	0	0	3	1	0	3
5	100	1	0	1	5	0	0	0	0
	100	2	0	0	0	0	0	2	1
	100	3	0	0	0	3	0	0	2
8	100	1	0	0	2	0	0	0	0
	100	2	0	0	0	0	0	1	0
	100	3	0	0	0	3	0	0	3
9	100	1	0	1	2	0	0	0	0
	100	2	0	0	0	0	0	1	0
	100	3	0	0	0	3	0	0	4
10	100	1	0	0	5	0	0	0	0
	100	2	1	0	0	0	1	0	0
	100	3	0	0	0	5	0	0	4
11	100	1	0	0	4	0	0	0	0
	100	2	0	0	0	0	0	0	0
	100	3	0	0	0	4	0	0	4
12	100	1	0	0	3	0	1	0	0
	100	2	1	0	1	0	0	0	0
	100	3	0	0	0	5	0	0	4
15	100	1	0	0	2	0	0	1	0
	100	2	0	0	0	0	0	1	0
	100	3	0	0	0	3	0	0	3
16	100	1	0	0	6	0	0	0	0
	100	2	0	0	0	0	0	0	0
	100	3	0	0	0	3	0	0	3
17	100	1	0	1	1	0	0	0	0
	100	2	0	0	0	0	0	0	1
	100	3	0	0	0	3	0	0	3
18	100	1	1	0	2	0	0	0	0
	100	2	0	0	0	0	0	1	0
	100	3	0	0	0	4	0	0	1
19	100	1	0	0	2	0	0	0	0
	100	2	0	0	0	0	0	0	0
	100	3	0	0	0	3	0	0	1
22	100	1	0	1	4	0	0	0	0
	100	2	0	0	0	0	0	0	0
	100	3	0	0	0	3	0	1	2
23	100	1	0	0	4	0	0	0	0
	100	2	0	0	0	0	0	0	1
	100	3	0	0	0	4	0	0	3
24	100	1	0	0	2	0	0	1	0
	100	2	0	1	0	0	0	0	0
	100	3	0	0	0	4	0	0	3
25	100	1	0	0	3	0	0	0	0
	100	2	0	0	0	1	0	0	0
	100	3	0	0	0	2	0	0	4
26	100	1	0	0	1	0	0	0	0
	100	2	0	1	0	1	0	0	0
	100	3	0	0	0	2	0	0	3
29	100	1	0	0	2	0	0	0	0
	100	2	0	0	1	0	0	0	0
	100	3	0	0	0	2	0	0	3
30	100	1	0	0	2	0	0	0	0
	100	2	0	0	0	0	1	0	0
	100	3	0	0	0	2	0	0	3

You need to find the number of defects per machine, then based on your results give your recommendations. You need to show your work and spread sheet if excel is used.

Answer 1

Compute the number of defective cords per machine and then construct the p-chart for each of the three machines.

p-chart for machine 1 is following

Machine 2

Machine 3

Based on the above p-charts, we can conclude that machine 2 process is out of control.

Therefore, machine 2 should be investigated for assignable causes of variation and those causes should be rectified.