O.L. Davies (1960, pp. 258-267) describes an experiment exploring the effect of certain factors on the...

  

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O.L. Davies (1960, pp. 258-267) describes an experiment exploring the effect of certain factors on the percentage yield of a nitration process, the product of which forms the basis of various medicinal products. The three factors investigated were as follows, each with two levels as described below. The time of addition of nitric acid: 2 hours or 7 hours. The time of stirring: either 1/2 hour or 4 hours. Heel: either present or absent. Heel is a slang term for residual product left in the container from the previous batch. It may not always be possible to completely remove this residue, which could possibly impact the yield in the succeeding batch. Suppose the data were as displayed below: Time of stirring 1/2 hour 4 hours No Heel With Heel Time of addition of nitric acid 2 hours 7 hours 87.2 88.4 82.0 83.0 2 hours 86.8 83.4 7 hours 89.3 83.5 Find the main effect of the time of addition of nitric acid (giving your answer to two decimal places; positive answers only). Use R to compute the ANOVA table for the additive model. That is, the model with no interaction terms. Provide the F statistic for the effect of the time of addition of nitric acid (to three decimal places). Provide the P-value for your test statistic in Part c), to three decimal places. Which of the following is a significant main effect when testing at the 5% significance level (select all that apply)? A. The time of addition of nitric acid B. Heel C. The time of stirring Davies, O.L. (1960): The Design and Analysis of Industrial Experiments. Oliver and Boyd. O.L. Davies (1960, pp. 258-267) describes an experiment exploring the effect of certain factors on the percentage yield of a nitration process, the product of which forms the basis of various medicinal products. The three factors investigated were as follows, each with two levels as described below. The time of addition of nitric acid: 2 hours or 7 hours. The time of stirring: either 1/2 hour or 4 hours. Heel: either present or absent. Heel is a slang term for residual product left in the container from the previous batch. It may not always be possible to completely remove this residue, which could possibly impact the yield in the succeeding batch. Suppose the data were as displayed below: Time of stirring 1/2 hour 4 hours No Heel With Heel Time of addition of nitric acid 2 hours 7 hours 87.2 88.4 82.0 83.0 2 hours 86.8 83.4 7 hours 89.3 83.5 Find the main effect of the time of addition of nitric acid (giving your answer to two decimal places; positive answers only). Use R to compute the ANOVA table for the additive model. That is, the model with no interaction terms. Provide the F statistic for the effect of the time of addition of nitric acid (to three decimal places). Provide the P-value for your test statistic in Part c), to three decimal places. Which of the following is a significant main effect when testing at the 5% significance level (select all that apply)? A. The time of addition of nitric acid B. Heel C. The time of stirring Davies, O.L. (1960): The Design and Analysis of Industrial Experiments. Oliver and Boyd.

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The mean percentages of yield for these two levels are Mean for 2 hours ... View the full answer