Problem #3

An inspector counted the percent of defectives (out of 100 samples) of a monthly billing

statement of a company. Using the following data set, construct a control chart that will

describe two sigma of the chance variation in the process (use the following questions as your

section titles).

Present your control chart

Identify the QC charts you chose and why

Specifically discuss the upper and lower control limits and any patterns in the data

Discuss the two sigma control limits and its importance

Discuss the process mean

Comment on randomness and if a pattern is present

Sample

Defects

1

9

2

11

3

12

4

6/n6

5

19

6

11

7

10

8

17

9

13

10

10

11