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1. South of the Borders, Inc. is a custom wallpapers and borders manufacturer. While their

products vary in visual design, the manufacturing process for each of the products is

similar. Each day a sample of 100 rolls of wallpaper border is sampled and the number

of defective rolls in the sample is noted. The number of defective rolls in samples from

25 consecutive production days follows. Determine all coordinates; construct &interpret the p chart.

Day Defective Rolls Day Defective Rolls

1 13 14 8

2 4 15 9

3 7 16 3

4 11 17 5

5 8 18 14

6 10 19 107 2 20 11

8 9 21 6

9 12 22 6

10 6 23 9

11 4 24 3

12 7 25 10

13 9

JAWAB:

Berikut adalah grafik peta kendali c:

Sample

Proportion

252321191715131197531

0,16

0,14

0,12

0,10

0,08

0,06

0,04

0,02

0,00

_P=0,0784

UCL=0,1590

LCL=0

P Chart of C1

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2. Scientific & Technical Materials, Inc. produces material for use as gaskets in scientific,

medical, and engineering equipment. Scarred material can adversely affect the ability of

the material to fulfill its intended use.

A sample of 40 pieces of material, taken at a rate of 1 per each 25 pieces of material

produced gave the results on the following slide. Use this information to construct andinterpret a C chart

Piece Scars Piece Scars Piece Scars Piece Scars

1 4 11 1 21 2 31 2

2 4 12 1 22 1 32 1

3 2 13 2 23 0 33 1

4 3 14 3 24 3 34 3

5 1 15 0 25 5 35 2

6 2 16 4 26 4 36 07 0 17 3 27 2 37 1

8 2 18 2 28 1 38 5

9 3 19 2 29 4 39 9

10 1 20 1 30 2 40 1

JAWAB:

Berikut adalah grafik dari peta kendalip:

Sample

Samp

leCount

37332925211713951

9

8

7

6

5

4

3

2

1

0

_C=2,25

UCL=6,75

LCL=0

1

C Chart of C2

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3. PT XYZ adalah suatu perusahaan pembuatan suatu produk industri. Ditetapkan

spesifikasi adalah : 2.40 0,05 mm. Untuk mengetahui kemampuan proses dan

mengendalikan proses itu bagian pengendalian PT XYZ telah melakukan pengukuran

terhadap 20 sampel. Masing-masing berukuran 5 unit (n=5).

Hitung proses capability data di bawah ini (cp dan cpk) ! Simpulkan

contoh pengukuran pada unit contoh (n=5)

sampel X1 (mm) X2 (mm) X3 (mm) X4 (mm) X5 (mm)

1 2.41 2.40 2.42 2.37 2.41

2 2.39 2.42 2.41 2.39 2.42

3 2.42 2.38 2.39 2.37 2.40

4 2.39 2.39 2.37 2.41 2.38

5 2.38 2.42 2.39 2.38 2.41

6 2.41 2.38 2.40 2.37 2.39

7 2.36 2.40 2.37 2.38 2.40

8 2.39 2.39 2.39 2.41 2.38

9 2.39 2.38 2.37 2.37 2.39

10 2.42 2.42 2.38 2.42 2.39

11 2.39 2.39 2.43 2.39 2.38

12 2.38 2.38 2.41 2.37 2.39

13 2.42 2.39 2.40 2.41 2.41

14 2.40 2.38 2.38 2.39 2.39

15 2.39 2.40 2.41 2.41 2.37

16 2.41 2.42 2.42 2.41 2.39

17 2.38 2.40 2.37 2.39 2.38

18 2.43 2.37 2.39 2.36 2.38

19 2.39 2.41 2.40 2.38 2.37

20 2.37 2.42 2.40 2.41 2.38

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JAWAB:

Berikut adalah grafik yang menunjukkan UCL dan LCL:

Berikut adalah grafik yang menunjukkan CP dan CPK:

Cp: 0,45 dan Cpk: 0,45

Sample

SampleMean

191715131197531

2,42

2,40

2,38

__X=2,394

UC L=2,41737

LCL=2,37063

Sample

SampleRange

191715131197531

0,08

0,06

0,04

0,02

0,00

_R=0,04051

UC L=0,08567

LCL=0

Xbar-R Chart of C3

2,432,422,412,402,392,382,372,36

LSL USL

Process Data

S ample N 100

StDev (Within) 0,0174181

StDev (Ov erall) 0,017335

LSL 2,37063

Target *

USL 2,41737

Sample Mean 2,394

Potential (Within) C apability

CC pk 0,45

O v erall C apability

Pp 0,45

P PL 0,45

P PU 0,45

Ppk

C p

0,45

C pm *

0,45

C P L 0,45

C P U 0,45

C pk 0,45

O bserv ed Performance

PPM < LSL 150000,00

PPM > USL 150000,00

PPM Total 300000,00

Exp. Within Performance

PPM < LSL 89845,39

PPM > USL 89845,39

PPM Total 179690,78

Exp. Ov erall Pe rformance

PPM < LSL 88807,29

PPM > USL 88807,29

PPM Total 177614,58

Within

Overall

Process Capability of C3

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Kesimpulan:

Karena Cp