An experiment was performed to compare four metal alloys. Various samples were made of each alloy, and their strengths were measured. The following data were obtained:
Type A: sample size 8, sample mean 10.50, sample standard deviation 1.02.
Type B: sample size 8, sample mean 9.22, sample standard deviation 0.86.
Type C: sample size 9, sample mean 6.32, sample standard deviation 1.13.
Type D: sample size 6, sample mean 11.39, sample t standard deviation 0.98.
(a) Construct the ANOVA table. What null hypothesis is tested by the ANOVA table? What bounds can you place on the p-value? What is your conclusion?
(b) Make a graphical representation of the differences between the alloy types. Which alloy type is the strongest? Which alloy type is the weakest?