4.9. The effect of three different lubricating oils on fuel economy in diesel truck engines is being studied. Fuel econo- my is measured using brake-specific fuel consumption after the engine has been running for 15 minutes. Five different truck engines are available for the study, and the experimenters conduct the following randomized complete block design. Truck Oil 1 2 3 4 5 1 0.500 0.634 0.487 0.329 0.512 2 0.535 0.675 0.520 0.435 0.540 3 0.513 0.595 0.488 0.400 0.510 (a) Analyze the data from this experiment. (b) Use the Fisher LSD method to make comparisons among the three lubricating oils to determine specifical- ly which oils differ in brake-specific fuel consumption. (c) Analyze the residuals from this experiment.