For each of the following designs in Exercises 7-1 through 7-8, answer the following questions.
(a) Compute the estimates of the effects and their standard errors for this design.
(b) Construct two-factor interaction plots and comment on the interaction of the factors.
(c) Use the t ratio to determine the significance of each effect with 0.05. Comment on your findings.
(d) Compute an approximate 95% CI for each effect. Compare your results with those in part (c) and comment.
(e) Perform an analysis of variance of the appropriate regression model for this design. Include in your analysis hypothesis tests for each coefficient, as well as residual analysis. State your final conclusions about the adequacy of the model. Compare your results to part (c) and comment.
An experiment involves a storage battery used in the launching mechanism of a shoulder-fired ground-to-air missile. Two material types can be used to make the battery plates. The objective is to design a battery that is relatively unaffected by the ambient temperature. The output response from the battery is effective life in hours. Two temperature levels are selected, and a factorial experiment with four replicates is run. The data are as follows.