Assignment:
Consider the data set shown in Table, summarizing recent numbers of errors in batches of 500 invoices
a. Find the percentage, p, for each batch.
b. Find the average percentage, p.
c. Find the center line for the percentage chart.
d. Find the control limits for the percentage chart.
e. Draw the percentage chart.
f. Comment on what you see in the percentage chart. In particular, is this process in control? How do you know?
g. Write a paragraph, as if to your supervisor, summarizing the situation and defending the action you feel is appropriate.
TABLE : Summaries of Defective Invoices in 25 Batches of n=500
|
Batch Identification Number
|
Batch
Number of Identification Errors, X Number
|
Number of Errors, X
|
|
1
|
58
|
14
|
51
|
|
2
|
57
|
IS
|
54
|
|
3
|
60
|
16
|
47
|
|
4
|
64
|
17
|
52
|
|
5
|
57
|
18
|
SO
|
|
6
|
53
|
19
|
62
|
|
7
|
53
|
20
|
56
|
|
8
|
74
|
21
|
60
|
|
9
|
40
|
22
|
67
|
|
10
|
54
|
23
|
50
|
|
11
|
56
|
24
|
60
|
|
12
|
54
|
25
|
67
|
|
13
|
60
|
|
|
Your answer must be typed, double-spaced, Times New Roman font (size 12), one-inch margins on all sides, APA format and also include references.