The data in following Table represent the number of defects detected in a series of 15 samples. Each sample contained 4 units.

Sample……………..Defective

1………………………26

2………………………23

3………………………32

4………………………35

5………………………25

6………………………32

7………………………20

8………………………0

9………………………6

10……………………..2

11……………………..5

12……………………..16

13……………………..5

14……………………..9

15……………………..12
Requirements:
a). What is the estimate of the average number of defects per sample?

b). Using 3-sigma limits, what is the UCL for the c-chart?

c). Using 3-sigma limits, what is the LCL for the c-chart?

d). For this c-chart, what conclusion can be drawn?