Problem: During a 4-week inspection period, the number of defects listed in the table were found in a sample of 400 electronic components. Construct a c chart for these data. Does it appear as though there existed an assignable cause of variation during the inspection period?
Date Number of defects Date Number of defects
1 7 11 6
2 8 12 8
3 9 13 16
4 8 14 2
5 3 15 4
6 9 16 2
7 5 17 6
8 6 18 5
9 15 19 3
10 9 20 7