A quality team at Milburn Textiles has been charged with setting up control charts to monitor a key dyeing process that has been improved and now stable. The ideal temperature for the process is 140 degrees. Too high a temperature results in excessively dark fabric. Too low a temperature results in streaking. Daily temperature readings are taken of the dye vats as shown below. [+2 pts.]
|
|
Observation
|
|
|
|
Day
|
1
|
2
|
3
|
4
|
5
|
Avg.
|
Range
|
|
1
|
136
|
137
|
144
|
141
|
138
|
139.2
|
8
|
|
2
|
143
|
138
|
140
|
140
|
139
|
140.0
|
5
|
|
3
|
140
|
141
|
144
|
137
|
135
|
139.4
|
9
|
|
4
|
139
|
138
|
141
|
140
|
141
|
140.0
|
2
|
|
5
|
137
|
141
|
143
|
140
|
138
|
139.2
|
6
|
|
6
|
142
|
141
|
140
|
139
|
138
|
140.0
|
4
|
|
7
|
143
|
139
|
143
|
140
|
140
|
141.4
|
3
|
|
8
|
139
|
138
|
141
|
140
|
136
|
139.0
|
5
|
|
9
|
140
|
141
|
143
|
141
|
139
|
140.2
|
5
|
|
10
|
139
|
141
|
142
|
140
|
136
|
139.6
|
6
|
a. What is the appropriate control chart(s) the quality team should use?
b. What are the appropriate control limits for the data?