Statistics Assignment

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Improve Phase Assignment

This phase is referred to as the proactive phase since the levels of input factors are changed to observe the effect on the output variable.

This phase will consider Analysis of Variance (ANOVA One Way and Two Way) and Design of Experiment (DOE)

Referred To:

Text Book: Implementing Six Sigma Smarter Solutions using Statistical Methods 2nd Edition By Forrest W Breyfogle III

a. Chapter 24

b. Chapter 25

Chapter 24

1. Exercise 7

2. Exercise 8

3. A manufacturer of steel wants to test the effect of the method of manufacture on the tensile strength of a particular type of steel. Four different methods have been tested and the data shown in Table 1. Test the significance of the effect at α = 0.05

Table 1

Methods Tensile Strength

1

2650

2765

2750

2600

2

2985

2975

2865

2890

3

2775

2620

2690

2700

4

2900

2885

2850

2950

Chapter 25

1. Exercise 2

2. A 2 Factor experiment was conducted to test whether the given factors affect the response variable. The data shown in Table 5 were collected for 3 levels for A and B respectively with 4 replicates.

i). Using α = 0.05, test for the significance of all possible effects.

Table 5

Factor A

Factor B 600 650 700

1

142, 113, 126, 130

115, 129, 109, 98

135, 120, 115, 110

2

122, 104, 118, 138

112, 104, 100, 119

144, 132, 120, 139

3

110, 126, 138, 120

122, 100, 118, 109

142, 130, 110, 125

3. A group of experimenters determine that 3 factors seem to have the most influence on a coating process. The measure the out come Y in terms of coating thickness in some consistent way.

B - Catalyst

0.1g/l

0.2g/l

C- Temperature

C - Temperature

15C

25C

15C

25C

A - Belt Rate

19

21

21

20

400 mm/min

17

20

19

18

Sum

36

41

40

38

20

20

25

26

800 mm/min

19

23

22

24

Sum

39

43

47

50

· Which factors and interactions effects are significant?

4. In a 23 Full Factorial experiment to test the effects of cutting speed (A), Feed rate (B) and Hardness (C) on the surface finish. The data in Table 7 shows one observation per each of the 8 combinations.

i). Conduct ANOVA at α = 0.05 to test for the significance of all possible effects.

Table 7

Cutting Speed A

300RPM 350RPM

Hardness C

30 40 30 40

Feed Rate B

0.002 10 15 8 13

0.004 14 16 10 12

5. An engineer is interested in the effects of cutting speed (A), tool geometry (B), and cutting angle (C) on the life (in hours) of a machine tool. Two levels of each factor are chosen, and three replicates of a 23 factorial design are run. The results follow:

Treatment

Replicate

A

B

C

Combination

I

II

III

-

-

-

(1)

22

31

25

+

-

-

a

32

43

29

-

+

-

b

35

34

50

+

+

-

ab

55

47

46

-

-

+

c

44

45

38

+

-

+

ac

40

37

36

-

+

+

bc

60

50

54

+

+

+

abc

39

41

47

· Estimate the factor effects. Which effects appear to be large?

3