Jamison Kovach Supply Company manufactures paper clips and other office products
ID: 358960 • Letter: J
Question
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 40. Results are given for the last 10 samples.
Sample
1
2
3
4
5
6
7
8
9
10
Defectives
5
7
3
6
6
5
4
5
2
11
1) The type of control chart that is best to monitor this process is ____?
a) Establish the control limits to include 99.73% of the random variation in defectives.
UCLp = ? enter your response as a number between 0 and 1, rounded to three decimal places).
LCLp =? (enter your response as a number between 0 and 1, rounded to three decimal places).
b) Has the process been in control?
Based on the developed control limits, the number of defectives has been ______.
c) If the sample size were 20 instead, how would your limits and conclusions change?
UCLp = ? (enter your response as a number between 0 and 1, rounded to three decimal places).
LCLp = ? (enter your response as a number between 0 and 1, rounded to three decimal places).
Based on the developed control limits, the number of defectives has been ______?
Sample
1
2
3
4
5
6
7
8
9
10
Defectives
5
7
3
6
6
5
4
5
2
11
Explanation / Answer
1) p-chart is best to use
a) p-bar = Number of defectives/Total sample size = (5+7+.......+11)/(40*10) = 0.135
s = sqrt(p-bar*(1-p-bar)/n)
n = 40
s = sqrt(0.135*(1-0.135)/40) = 0.054
z = 3 for 99.73%
UCL = p-bar + z*s = 0.135 +3*0.054 = 0.297
LCL = p-bar - z*s = 0.135 -3*0.054 = -0.027. As it cannot be negative hence 0.000
b)
Yes, process is in control as defect % is within range
The number of defects has been lower
c) Now, n = 20
s = 0.076
UCL = 0.135 + 3*0.076 = 0.364
LCL = 0.135 - 3*0.076 = -0.094. Hence, 0
The number of defects has been lower
Sample Defectives Defect % 1 5 0.125 2 7 0.175 3 3 0.075 4 6 0.15 5 6 0.15 6 5 0.125 7 4 0.1 8 5 0.125 9 2 0.05 10 11 0.275Related Questions
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