Site icon assignmentpress.com

1. Suppose 20 respirator masks are examined every thirty minutes and the number of defective units…

1. Suppose 20 respirator masks are examined every thirty minutes and the number of defective units are recorded per 8-hour shift. The total number examined on a given shift is equal to n = 20(16) = 320. Table 18.5 gives the results for 30 such shifts. The center line for the p-chart is equal to the proportion of defectives for the 30 shifts, and is given by total number of defectives divided by the total number examined for the 30 shifts, or

Don't use plagiarized sources. Get Your Custom Essay on
1. Suppose 20 respirator masks are examined every thirty minutes and the number of defective units…
Just from $13/Page
Order Essay

2. For the data in Table 18.5, the centerline is given by n-p = 320(.0075) =  2.4 and the control limits are LCL = 2.4 – 4.63 = -2.23, which we take as 0, and UCL = 2.4 + 4.63 = 7.03. If 8 or more defectives are found on a given shift, the process is out of control. The MINITAB solution is found by using the pull-down sequence

3. For the data in Table 18.5, the centerline is given by = 320(.0075) = 2.4 and the control limits are LCL = 2.4 – 4.63 = -2.23, which we take as 0, and UCL= 2.4 + 4.63 = 7.03. If 8 or more defectives are found on a given shift, the process is out of control. The MINITAB solution is found by using the pull-down sequence

Shift #

Number

Proportion

 

Number

Proportion

1

Defective

Defective

 

Defective

Defective

2

Xi

Pi = X/n

Shift

Xi

Pi = X/n

3

1

0.003125

16

2

0.006250

4

2

0.006250

17

0

0.000000

5

2

0.006250

18

4

0.012500

6

0

0.000000

19

1

0.003125

7

4

0.012500

20

7

0.021875

8

4

0.012500

21

4

0.012500

9

4

0.012500

22

1

0.003125

10

6

0.018750

23

0

0.000000

11

4

0.012500

24

4

0.012500

12

0

0.000000

25

4

0.012500

13

0

0.000000

26

3

0.009375

14

0

0.000000

27

2

0.006250

15

1

0.003125

28

0

0.000000

Shift #

0

0.000000

29

0

0.000000

1

7

0.021875

30

5

0.015625

Exit mobile version