Assignment 3

Due Date

Friday, September 21, 2012

Data Source

There are two data sets for this assignment:

1. quinn1.csv, the comma-delimited text file that you analyzed in Assignment 1 and Assignment 2.
2. pines.txt, a tab-delimited text file.

Questions

1. Reproduce the two-factor interaction plot you created in Question 3 of Assignment 2 for the egg count data set quinn1.csv. Add to that graph difference-adjusted confidence intervals for each mean that allow you to make all pairwise comparisons between the displayed means. What do you conclude from that display?
2. The diameters of three species of pine trees were measured. Fifteen adult individuals, five from each species, were randomly selected at four different locations. The four locations are of no special interest; it was hoped that they would be representative of the places where these three species are found together naturally. The data are contained in the tab-delimited text file pines.txt.
   1. Carry out an appropriate statistical analysis to test whether the tree species differ in their mean diameters.
   2. Use the results of your analysis to obtain 95% confidence intervals for the mean diameters of the three species.

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