A production manager at a tire manufacturing plant has inspected the number of defective tires in twenty random samples with twenty observations each.
Following are the number of defective tires found in each sample:
|
Number of
|
Number of
|
|
|
Sample
|
Defective
|
Observations
|
Fraction
|
|
Number
|
Tires
|
Sampled
|
Defective
|
|
1
|
3
|
20
|
.15
|
|
2
|
2
|
20
|
.10
|
|
3
|
1
|
20
|
.05
|
|
4
|
2
|
20
|
.10
|
|
5
|
1
|
20
|
.05
|
|
6
|
3
|
20
|
.15
|
|
7
|
3
|
20
|
.15
|
|
8
|
2
|
20
|
.10
|
|
9
|
1
|
20
|
.05
|
|
10
|
2
|
20
|
.10
|
|
11
|
3
|
20
|
.15
|
|
12
|
2
|
20
|
.10
|
|
13
|
2
|
20
|
.10
|
|
14
|
1
|
20
|
.05
|
|
15
|
1
|
20
|
.05
|
|
16
|
2
|
20
|
.10
|
|
17
|
4
|
20
|
.20
|
|
18
|
3
|
20
|
.15
|
|
19
|
1
|
20
|
.05
|
|
20
|
1
|
20
|
.05
|
|
Total
|
40
|
400
|
|
Construct a three-sigma control chart (z=3) with this information.