1. Jamison Kovach Supply Company manufactures paper clips and other office products. Although inexpensive, paper clips have provided the firm with a high margin of profitability. Sample size is 200. Results are given for the last 10 samples:
|
Sample
|
1
|
2
|
3
|
4
|
5
|
6
|
7
|
8
|
9
|
10
|
|
Defectives
|
5
|
7
|
4
|
4
|
6
|
3
|
5
|
6
|
2
|
8
|
a) Establish upper and lower control limits for the control chart and graph the data.
b) Has the process been in control?
c) If the sample size were 100 instead, how would your limits and conclusions change?
2. Peter Ittig's department store, Ittig Brothers, is Amherst's largest independent clothier. The store receives an average of six returns per day. Using z = 3, would nine returns in a day warrant action?