In a textile processing plant the quality of the output fabric is believed to be influenced by four factors (A, B, C, and D), each of which can be controlled at three levels. The fabric is classified into three categories: acceptable, second-class, or reject. An L9 orthogonal array is selected for the design factors, with the factors A,B, C, and D assigned to columns 1, 2, 3, and 4, respectively.
The observations are shown in Table. Management wants to eliminate reject product altogether. Conduct an accumulation analysis, and determine the optimal settings of the design factors.
|
Experiment
|
Factor
|
Quality of fabric
|
|
A
|
B
|
C
|
D
|
Acceptable
|
Second Class
|
Reject
|
|
1
|
1
|
1
|
1
|
1
|
0
|
1
|
0
|
|
2
|
1
|
2
|
2
|
2
|
1
|
0
|
0
|
|
3
|
1
|
3
|
3
|
3
|
0
|
1
|
0
|
|
4
|
2
|
1
|
2
|
3
|
0
|
1
|
0
|
|
5
|
2
|
2
|
3
|
1
|
0
|
0
|
1
|
|
6
|
2
|
3
|
1
|
2
|
1
|
0
|
0
|
|
7
|
3
|
1
|
3
|
2
|
0
|
0
|
1
|
|
8
|
3
|
2
|
1
|
3
|
0
|
1
|
0
|
|
9
|
3
|
3
|
2
|
1
|
1
|
0
|
0
|