l7 - STAT 350 Fall 2008 Lab #7 Solution CORRECTED DUE:...

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STAT 350 – Fall 2008 Lab #7 Solution CORRECTED DUE: Monday, November 17, 2008 @ the beginning of class For the following problems, do the analysis using SAS. Please put all SAS input (Editor window) and all SAS output (Output window, NOT the Log window) as an appendix. Nothing pasted directly from SAS should be given as an answer to the questions below! The Experiment A wood scientist (yes, there are such people. .. even right here at Purdue) has come to you for help analyzing an experiment. He had wanted to examine the durability of wood used for decking. Deterioration of wood in use is commonly caused by decay fungi, certain insects (including termites) as well as other organisms, and weathering. He wanted to examine various species of wood and various preservatives. He used 3 species of hardwood: Maple, Ash, and Red Oak. He also used 4 species of softwood: Spruce, Northern White Cedar, Eastern Red Cedar, and Redwood. He used 4 types of preservatives. He tested 2 oil-based preservatives: creosote and pentachlorophenol (PCP). He also tested 2 water-based preservatives: chromated copper arsenate (CCA) and ammoniacal copper arsenate (ACA). He had 20 two-by-four boards of each species: of these 5 were treated with creosote, 5 with PCP, 5 with CCA, and 5 with ACA. The boards were dried and weighed then placed outdoors (all in the same experimental plot) for 10 years. At the end of 10 years, the boards were collected, dried, and re-weighed. For each board, the dry weight-loss (in grams) was recorded. The data are available in the accompanying Excel file. 1. Analyze the data as a 2-way ANOVA, with "preservative" and "species" as the 2 factors (you do not have to worry about softwood versus hardwood or water-based versus oil-based preservatives. Present the ANOVA table (with p -values) in a report-quality table. Source df Sums of Squares Mean Squares F p Species 6 35388.36 5898.06 27.93 <0.0001 Preservative 3 13870.32 4623.44 21.90 <0.0001 S × P 18 8395.37 466.41 2.21 0.0063 Error 112 23647.46 211.14 Total 139 81301.51 2. Conduct Tukey's multiple comparison procedure on the two main effects and present your results (with the means for each level) using the line method discussed in class (you may draw the lines in by hand). Spruce Maple Ash Red Oak White Cedar Redwood Red Cedar 76.660 73.530 65.075 51.230 47.335 42.950 29.750 Creosote CCA PCP ACA 64.343 59.603 58.529 38.400 Lab #7 - Solution Page 1 of 1
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3. Give interaction plots (I recommend making these in Excel). Make 2 separate plots. One
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l7 - STAT 350 Fall 2008 Lab #7 Solution CORRECTED DUE:...

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