1. Computer upgrades have a nominal time of 80 minutes. Samples of 10 observations each have been taken, and the results are as listed. Historical data show that the standard deviation of the upgrade times is 0.5 minutes.
|
|
Sample 1
|
Sample 2
|
Sample 3
|
Sample 4
|
Sample 5
|
|
Observation 1
|
79.2
|
80.5
|
79.6
|
78.9
|
79.7
|
|
Observation 2
|
78.8
|
78.7
|
79.6
|
79.4
|
80.6
|
|
Observation 3
|
80.0
|
81.0
|
80.4
|
79.7
|
80.5
|
|
Observation 4
|
78.4
|
80.4
|
80.3
|
79.4
|
80.0
|
|
Observation 5
|
81.0
|
80.1
|
80.8
|
80.6
|
81.1
|
|
Observation 6
|
77.8
|
78.8
|
80.4
|
77.7
|
79.8
|
|
Observation 7
|
79.3
|
79.6
|
79.4
|
80.6
|
81.0
|
|
Observation 8
|
80.4
|
80.5
|
78.7
|
80.8
|
80.6
|
|
Observation 9
|
81.1
|
79.4
|
81.3
|
81.0
|
80.8
|
|
Observation 10
|
80.9
|
80.2
|
80.5
|
79.2
|
77.9
|
|
Sample Mean, X-bar
|
79.69
|
79.92
|
80.1
|
79.73
|
80.20
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
What are the 3-sigma (z= 3) control limits to be used in the mean (X-bar) control chart and what is the decision based on this X-bar chart?
A)
B)
C)
D)
Computer upgrades have a nominal time of 80 minutes. Samples of 10 observations each have been taken, and the results are as listed. Historical data show that the standard deviation of the upgrade times is 0.5 minutes.
|
|
Sample 1
|
Sample 2
|
Sample 3
|
Sample 4
|
Sample 5
|
|
Observation 1
|
79.2
|
80.5
|
79.6
|
78.9
|
79.7
|
|
Observation 2
|
78.8
|
78.7
|
79.6
|
79.4
|
80.6
|
|
Observation 3
|
80.0
|
81.0
|
80.4
|
79.7
|
80.5
|
|
Observation 4
|
78.4
|
80.4
|
80.3
|
79.4
|
80.0
|
|
Observation 5
|
81.0
|
80.1
|
80.8
|
80.6
|
81.1
|
|
Observation 6
|
77.8
|
78.8
|
80.4
|
77.7
|
79.8
|
|
Observation 7
|
79.3
|
79.6
|
79.4
|
80.6
|
81.0
|
|
Observation 8
|
80.4
|
80.5
|
78.7
|
80.8
|
80.6
|
|
Observation 9
|
81.1
|
79.4
|
81.3
|
81.0
|
80.8
|
|
Observation 10
|
80.9
|
80.2
|
80.5
|
79.2
|
77.9
|
|
Sample Range
|
3.3 |
2.3 |
2.6 |
3.4 |
3.2 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
What are the control limits to be used in the Range (R) control chart and what is the decision based on this R chart?
Fixing a quality problem will often cost money; to minimize these costs it is best to find and fix the problem _______.
Which one of the following statements is incorrect about quality control activities, inspection and control charts?A)
B)
C)
D)
E)