Applied Statistics and Probability for Engineers

14-10 RESPONSE SURFACE METHODS AND DESIGNS (CD) 567

14-54. An article in Rubber Chemistry and Technology

(Vol. 47, 1974, pp. 825–836) describes an experiment that

studies the Mooney viscosity of rubber to several variables,

including silica filler (parts per hundred) and oil filler (parts

per hundred). Data typical of that reported in this experiment

follow, where

x 1 

silica 60

15

, x 2 

oil 21

15

ABCDE Free Height

7.78 7.78 7.81

8.15 8.18 7.88

7.50 7.56 7.50

7.59 7.56 7.75

7.54 8.00 7.88

7.69 8.09 8.06

7.56 7.52 7.44

7.56 7.81 7.69

7.50 7.56 7.50

7.88 7.88 7.44

7.50 7.56 7.50

7.63 7.75 7.56

7.32 7.44 7.44

7.56 7.69 7.62

7.18 7.18 7.25

7.81 7.50 7.59

Coded levels

x 1 x 2 y

 1  1 13.71

1  1 14.15

 1 1 12.87

1 1 13.53

 1  1 13.90

1  1 14.88

 1 1 12.25

 1 1 13.35

(a) What type of experimental design has been used?

(b) Analyze the data and draw appropriate conclusions.

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