A textile manufacturer wants to set up a control chart for i
A textile manufacturer wants to set up a control chart for irregularities per 100 square yards of carpet. The following data were collected from a sample of twenty 100-square-yard pieces of carpet:
A) Using these data, set up a c-chart with z = 3
B) Suppose that the next five samples had 15,18,12, 22 and 21 irregularities. What do you conclude?
| Sample | Irregularities | 
| 1 | 11 | 
| 2 | 8 | 
| 3 | 9 | 
| 4 | 12 | 
| 5 | 4 | 
| 6 | 16 | 
| 7 | 5 | 
| 8 | 8 | 
| 9 | 17 | 
| 10 | 10 | 
| 11 | 11 | 
| 12 | 5 | 
| 13 | 7 | 
| 14 | 12 | 
| 15 | 13 | 
| 16 | 8 | 
| 17 | 19 | 
| 18 | 11 | 
| 19 | 9 | 
| 20 | 10 | 
Solution

