Problem: In a follow-up experiment, we have been able to collect data on several samples of each of Alloy A and B at 3 different temperature excursions (25ο C, 80ο C and 135ο C) during thermal cycling. The Mean Time to Failure (MTTF) results are shown in the table below:
|
Alloy
|
25ο C
|
80ο C
|
135ο C
|
|
A
|
|
|
|
|
Sample 1
|
4000 hours
|
2500 hours
|
1000 hours
|
|
Sample 2
|
4200 hours
|
2900 hours
|
1650 hours
|
|
Sample 3
|
3740 hours
|
2310 hours
|
950 hours
|
|
B
|
|
|
|
|
Sample 1
|
3850 hours
|
2350 hours
|
875 hours
|
|
Sample 2
|
3960 hours
|
2470 hours
|
1075 hours
|
|
Sample 3
|
3740 hours
|
2200 hours
|
810 hours
|
(a) Using Excel's ANOVA tool (With Replication), determine which factors are significant.
(b) Draw the Mean Effects graphs to confirm that the interaction between alloy type and temperature is not significant.
(c) Use Excel's Regression tool to derive the equation linking MTTF with the test variables. Because of part (b), exclude the interaction variable in the linking equation.
(d) Determine the goodness of the linear fit.