Consider the earth-moving experiment in Exercise 14-34. The experiment actually used two different operators with the production in columns 1 and 3 from operator 1 and 2, respectively. Analyze the results from only columns 1 and 3 handled as blocks.

(a) Assuming that the operator is a nuisance factor, estimate the factor effects.

(b) Based on a normal probability plot of the effect estimates, identify a model for the data from this experiment.

(c) Conduct an ANOVA based on the model identified in part (a). What are the conclusions?

(d) Analyze the residuals and plot residuals versus the predicted production.

(e) Compare the results from this analysis to the previous analysis that did not use blocking.

Exercise 14-34

An article in Journal of Construction Engineering and Management (€œAnalysis of Earth-Moving Systems Using Discrete€”Event Simulation,€ 1995, Vol. 121(4), pp. 388€“396) considered a replicated two-level factorial experiment to study the factors most important to output in an earth-moving system. Handle the experiment as four replicates of a 2⁴ factorial design with response equal to production rate (m3 / h). The data are shown in the following table.

Production (m'/h) Number of Trucks Passes Load-pass Time Travel per Load Row Time 2 176.3 179.6 179.8 173.1 373.1 375.9 372.4 361.1 153.2 153.6 150.8 148.6 4 226.1 220.0 225.7 218.5 154.2 242.3 156.9 155.4 152.2 233.5 242.0 233.6 122.7 119.6 120.9 118.6 135.7 130.9 135.5 131.6 44.2 124.2 44.0 43.5 43.6 10 123.3 122.8 121.6 42.5 11 42.0 42.4 41.0 12 116.3 117.3 115.6 114.7 42.1 13 42.6 42.8 42.9 14 119.1 119.5 116.9 117.2 15 39.6 39.7 39.5 39.2 105.3 16 107.0 104.2 103.0 |III IIII + + + + + + + + |III + + + + III| + + + + I + +| I + +| I + + | I + + +I + +| + I +| + | +| + 6789