Question

An aircraft firm is considering three different alloys for use in the wing construction of a new airplane. Each alloy can be produced in four different thicknesses (1 = thinnest, 4 = thickest). Two test samples are constructed for each combination of alloy type and thickness, then each of the 24 test samples is subjected to a laboratory device the severely flexes it until failure occurs. For each test sample the number of flexes before failure is recorded, with the results shown in the Aircraft worksheet in the ANOVA HW data workbook on Moodle.

a) Use JMP to fit a two-way ANOVA to the data. Using alpha = 0.05 draw conclusions for the ANOVA. Make sure you state your conclusion in the context of the problem.

b) Does there appear to be a need to include the alloy type / thickness interaction term?

c) Use JMP to fit a two-way ANOVA with interaction to the data. Using alpha= 0.05 draw conclusions for the ANOVA. Make sure you state your conclusion in the context of the problem.

Alloy    Thickness    Flexes

Alloy A Thickness 1    804

Alloy A Thickness 1    816

Alloy A    Thickness 2 819

Alloy A    Thickness 2 813

Alloy A    Thickness 3    820

Alloy A    Thickness 3    821

Alloy A Thickness 4 806

Alloy A Thickness 4    805

Alloy B    Thickness 1 836

Alloy B Thickness 1 828

Alloy B    Thickness 2    844

Alloy B    Thickness 2    836

Alloy B Thickness 3    814

Alloy B Thickness 3    811

Alloy B Thickness 4 811

Alloy B    Thickness 4 806

Alloy C    Thickness 1    804

Alloy C    Thickness 1 808

Alloy C Thickness 2 807

Alloy C Thickness 2    819

Alloy C    Thickness 3 819

Alloy C    Thickness 3    829

Alloy C Thickness 4    827

Alloy C    Thickness 4 835

Answer 1