An aluminum master alloy manufacturer produces grain refiners in ingot form.  The company produces the product in four furnaces.  Each furnace is known to have its own unique operating characteristics, so any experiment run in the foundry that involves more than one furnace will consider furnaces as a nuisance variable.  The process engineers suspect that stirring rate impacts the grain size of the product.  Each furnace can be run at four different stirring rates.  A randomized block design is run for a particular refiner and the resulting grain size data is as follows.   Furnace Stirring Rate 1 2 3 4 5 8 4 5 6 10 14 5 6 9 15 14 6 9 2 20 17 9 3 6 (a) Plot the residuals versus furnace and stirring rate. Does this plot convey any useful information? (b) What should the process engineers recommend concerning the choice of stirring rate and furnace for this particular grain refiner if small grain size is desirable?

In a large scale study of energy conservation in single family homes, 20 homes were randomly selected from homes built in a housing development in southern England. Ten of the houses, randomly selected from the 20 houses selected for the study, were constructed with standard levels of insulation (70 mm of roof insulation and 50 mm of insulation in the walls). The other 10 houses were constructed with extra insulation (120 mm of roof insulation and 100 mm of insulation in the walls). Each house was heated with a gas furnace and energy consumption was monitored for eight years. The data shown below give annual gas consumption in MWh for each of the 20 houses. Standard Insulation Extra Insulation 13.8 15.1 17.8 13.9 18.0 15.9 17.3 17.2 16.9 15.2 19.9 13.8 13.6 11.3 17.6 13.2 15.9 18.8 12.3 14.0 Sample means Sample Standard Deviation 16.31 14.84 2.38 2.12

A car dealer is interested in comparing the average gas mileages of four different car models. The dealer believes that the average gas mileage of a particular car will vary depending on the person who is driving the car due to different driving styles. Because of this, he decides to use a randomized block design. He randomly selects five drivers and asks them to drive each of the cars. He then determines the average gas mileage for each car and each driver. Can the dealer conclude that there is a significant difference in average gas mileages of the four car models? The results of the study are as follows.  Average Gas Mileage Driver Car A Car B Car C Car D Driver 1 3232 2222 3030 3939 Driver 2 2121 3939 3838 3737 Driver 3 2626 3131 3232 3939 Driver 4 3838 4040 2323 3434 Driver 5 3131 2929 2121 2222 Copy Data ANOVA Source of Variation SSSS dfdf MSMS Rows 174.2000174.2000 44 43.550043.5500 Columns 91.600091.6000 33 30.533330.5333 Error 607.4000607.4000 1212…

A biologist wants to determine if different temperatures (15oC, 25oC, or 35oC) and amounts of sunlight (partial or full) will affect the growth of plants. He will test each combination of temperature and sunlight by randomly assigning 15 plants to each of the combinations. What type of sampling is described in this study? one sample paired data two samples more than two samples

According to the 2000 U.S. Census Bureau, in 2000, 9.5 percent of children in the state of Ohio were not covered by private or government health insurance. In the neighboring state of Pennsylvania, 4.9 percent of children were not covered by health insurance. Assume that these proportions are parameters for the child populations of the respective states. If a random sample of size 100 children is drawn from the Ohio population, and an independent random sample of size 120 is drawn from the Pennsylvania population, what is the probability that the samples would yield a difference, ^p1 - ^p2 of .09 or more?

A car dealer is interested in comparing the average gas mileages of four different car models. The dealer believes that the average gas mileage of a particular car will vary depending on the person who is driving the car due to different driving styles. Because of this, he decides to use a randomized block design. He randomly selects five drivers and asks them to drive each of the cars. He then determines the average gas mileage for each car and each driver. Can the dealer conclude that there is a significant difference in average gas mileages of the four car models? The results of the study are as follows.  Average Gas Mileage Driver Car A Car B Car C Car D Driver 1 3636 3636 3535 2929 Driver 2 2525 3737 3737 3838 Driver 3 2323 3939 2525 3636 Driver 4 2121 3838 3939 2727 Driver 5 2424 3434 3636 3030 Copy Data ANOVA Source of Variation SSSS dfdf MSMS Rows 47.500047.5000 44 11.875011.8750 Columns 334.9500334.9500 33 111.6500111.6500 Error 315.3000315.3000…

Imagine you work for a large company that sells a variety of cleaning supplies deigned to prevent the spread of viruses. You decide to investigate what the best method for preventing the spread of viruses is, if only one method is used. You design experiments with the following groups: hand sanitizer only, hand washing without soap, hand washing with soap, along with a control group. Each group has 181 observations during testing, beginning with a certain amount of the viruses present before treatment is applied. The amount of germs is being measured. You find a sum of squares between treatments of 578.59, along with a sum of squares error of 5022.05. Using this information, what is the F-statistic of your analysis?