A manufacturing plant make wind mill assemblies & can produce 50 units in a month in two period of 15 days each ; following is the data for number of defects arising per month.
|
Month
|
JAN
|
FEB
|
MAR
|
APR
|
MAY
|
JUN
|
JUL
|
AUG
|
SEP
|
OCT
|
NOV
|
DEC
|
|
Number of Defects per period
|
4
3
|
3
2
|
1
0
|
4
5
|
6
7
|
7
7
|
9
6
|
5
4
|
2
3
|
0
2
|
2
3
|
4
3
|
Questions:
1. Which control chart should be used for the above data and why?
2. Make the appropriate control chart on a graph paper.
3. Interpret the chart and give your recommendation. Whether the process is in control or not?