5.20 The percentage of hardwood concentration in raw pulp, the vat pressure. and the cooking time of the pulp are being investigated for their effects on the strength of paper. Three levels of hardwood concentration. three levels of pressure, and two cooking times are selected. A factorial experiment with two replicates is conducted, and the following data are obtained: Cooking Time 3.0 Hours Percentage of Hardwood \"9+ Concentration 400 500 650 2 196.6 197.7 199.8 196.0 196.0 199.4 4 198.5 196.0 198.4 197.2 196.9 197-6 8 197.5 195.6 197.4 196.6 196.2 198.1 Cooking Time 4.0 Hours Percentage of Hardwood .__._P"e Concentration 400 500 650 2 198.4 199.6 200.6 1 98.6 200.4 200.9 4 197.5 198.7 199.6 198.1 198.0 199.0 8 197.6 197.0 198.5 198.4 197.8 199.8 (a) Analyze the data and draw conclusions. Use ti = 0.05. (a) Analyze the data and draw conclusions. Use a = 0.05. (I1) Prepare appropriate residual plots and comment on the model's adequacy. (e) Under what set of conditions would you operate this process? Why? 5.37 Reconsider the three-factor factorial experiment in Problem 5.20. Suppose that this experiment had been con- ducted in two blocks, with each replicate a block. Assume that the observations in the data table are given in order, that is. the rst observation in each cell comes from the rst replicate. and so on. Reanalyze the data as a factorial experiment in blocks and estimate the variance component for blocks. Does it appear that blocking was useful in this experiment