Do the following problems from Rosner, Fundamentals of Biostatistics, 5th Edition. Your response to each question should be in the form of a report. Prepare the report in a word processor, integrating graphics and discussion.
Use a variety of graphs, including, where appropriate, comparative box plots.
Do all your calculations and tables in R. For the quintiles, you will need to make a 5 by 5 table for each pair you are comparing. In addition, display the four DR variables on a scatterplot matrix, and repeat for the four FFQ variables.
Find the Niagara River Pollution Case Study archived at http://ssc.ca/documents/case_studies/1999/E-niagara.html. Extract the "PCB in water" readings at Fort Erie and Niagara-on-the-Lake. Study the two time sequences graphically, looking for the following features: trend, cyclic effects, change-points, autocorrelation. Are the "detection limits" a problem? Does a log transformation make the data easier to interpret? Are there differences between the two stations?
In Exercise #2 you drew histograms and density estimates for samples of different sizes from the standard normal distribution and the chi-square distribution on 3 degrees of freedom. How large does the sample size have to be for the data to give a reliable indication of the shape of the underlying distribution? Give a few graphs to support your conclusion.