Every employee in a check-processing department goes through a four-month training period, after which the employee is responsible for their operation. The work of one employee who has been on the job for eight months is being studied. Given Table shows the number of errors and the number of items sampled over a period of two months.
The first 16 samples were each chosen from 400 items, and the remaining 9 samples were each chosen from 300 items. Determine whether the employee's performance can be judged stable. Comment on the capability of the employee.
|
Sample
|
Errors
|
Items Sampled
|
Sample
|
Errors
|
Items Sampled
|
|
1
|
12
|
400
|
14
|
18
|
400
|
|
2
|
9
|
400
|
15
|
8
|
400
|
|
3
|
13
|
400
|
16
|
6
|
400
|
|
4
|
7
|
400
|
17
|
4
|
300
|
|
5
|
6
|
400
|
18
|
6
|
300
|
|
6
|
10
|
400
|
19
|
5
|
300
|
|
7
|
14
|
400
|
20
|
8
|
300
|
|
8
|
7
|
400
|
21
|
10
|
300
|
|
9
|
5
|
400
|
22
|
7
|
300
|
|
10
|
6
|
400
|
23
|
4
|
300
|
|
11
|
4
|
400
|
24
|
5
|
300
|
|
12
|
9
|
400
|
25
|
3
|
300
|
|
13
|
11
|
400
|
|
|
|