Quality Control
1. Write a one-page essay (at most 12pts 1.5 space) on the pros and cons of push versus pull manufacturing systems.
2. What is the purpose of a control chart?
3. Briefly explain the purpose of each of the following control charts
a. X-bar
b. Range
c. p-chart
d. c-chart
4. The time spent in a local medical clinic is to be investigated. Historically, the process has had a standard deviation equal to .146. The means of 39 samples of n=14 are:
|
Sample
|
Mean
|
Sample
|
Mean
|
Sample
|
Mean
|
Sample
|
Mean
|
|
1
|
3.86
|
11
|
3.88
|
21
|
3.84
|
31
|
3.88
|
|
2
|
3.9
|
12
|
3.86
|
22
|
3.82
|
32
|
3.76
|
|
3
|
3.83
|
13
|
3.88
|
23
|
3.89
|
33
|
3.83
|
|
4
|
3.81
|
14
|
3.81
|
24
|
3.86
|
34
|
3.77
|
|
5
|
3.84
|
15
|
3.83
|
25
|
3.88
|
35
|
3.86
|
|
6
|
3.83
|
16
|
3.86
|
26
|
3.9
|
36
|
3.8
|
|
7
|
3.87
|
17
|
3.82
|
27
|
3.81
|
37
|
3.84
|
|
8
|
3.88
|
18
|
3.86
|
28
|
3.86
|
38
|
3.79
|
|
9
|
3.84
|
19
|
3.84
|
29
|
3.98
|
39
|
3.85
|
|
10
|
3.8
|
20
|
3.87
|
30
|
3.96
|
|
|
a) Construct an x bar-chart for this process with three-sigma limits. Is the process in control?
b) Analyze the data using a median run test and an up/down run test. What can you conclude?