DOE II-PracProb

# DOE II-PracProb - 1(c Construct the ANOVA table(Use SST =...

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Design of Experiments II: Practice Problems 1. A router is used to cut registration notches in printed circuit boards. The average notch dimension is satisfactory, but there is too much variability in the process. This excess variability leads to problems in board assembly. A quality control team assigned to this project decided to use a designed experiment to study the process. The team considered two factors: bit size (A) and speed (B). Two levels were chosen for each factor (bit size A at 1/16 inch and 1/8 inch and speed B at 40 rpm and 80 rpm) and a 2 2 design was set up. Four boards were tested at each of the four runs in the experiment, and the resulting data are shown in the following table: Treatment A B Vibration - - + - - + + + 18.2 18.9 12.9 14.4 27.2 24.0 22.4 22.5 15.9 14.5 15.1 14.2 41.0 43.9 36.3 39.9 (a) Compute the main effects and interaction effect. (b) Compute the sum of squares associated with the effects.

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Unformatted text preview: 1 (c) Construct the ANOVA table. (Use SST = 1709.836) (d) Using alpha = 5%, test to determine whether there is any significant effect on vibration due to (i) Bit size (ii) Speed (iii) Interaction between bit size and speed (e) Write down the fitted regression model. 2 2. An experiment was performed to investigate the surface finish of a metal part. The experiment is a 2 3 factorial design in the factors feed rate (A), depth of cut (B), and tool angle (C). The observed surface-finish data for this experiment are presented in the following table: Treatment A B C Surface Finish- - -+ - -- + -+ + -- - + + - +- + + + + + 9, 7 10, 12 9, 11 12, 15 11, 10 10, 13 10, 8 16, 14 (a) Compute the factor effects and sum of squares associated with the effects. 3 (b) Construct the ANOVA table. (Use SST = 92.9375) (c) Which effects have significant impact on the surface-finish? (use alpha = 0.05) 4...
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DOE II-PracProb - 1(c Construct the ANOVA table(Use SST =...

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