Ten samples of 15 parts each were taken from an ongoing process to establish a

Ten samples of 15 parts each were taken from an ongoing process to establish a pchart for control. The samples and the number of defectives in
each are shown in the following table:

Number of

Number of

Defective Items

Defective Items

Sample

n

in the Sample

Sample

n

in the Sample

1

15

3

6

15

2

2

15

1

7

15

0

3

15

0

8

15

3

4

15

0

9

15

1

5

15

0

10

15

0

a. Develop a p -chart for 95 percent confi dence (1.96 standard deviation).

b. Based on the plotted data points what comments can you make?