A factory manufacturing small bolts. To check the quality of the bolts, the manufacturer selected 20 samples of same size 100 from the manufacturing process time to time. He/she visually inspected each selected bolt for certain defects. After the inspection, he she obtained the following data:
Sample Number
Proportion Defective
1
2
3
0.08
13
4
5
6
7
8
9
10
0.10
0.04
0.15
0.08
0
0.01
17
0.05
0.05
0.08
Sample Number
11
12
14
15
16
18
19
0.01
20
Proportion Defective
0.10
0
0.06
0.05
0.03
0.20
0.05
0.07
0.08
Estimate the proportion defective of the process. Does the process appear to be under control with respect to the proportion of defective bolts?