This test is to be written in the BSB Computer Lab. The duration of the test is 2 hours.

Any calculators and one sheet of notes (8.5" x 11", one side only) are permitted. You may refer to the STAT 3N03 2002-2003 web site, but you may not consult any other web pages or e-mail.

Use R to do your analyses and draw graphs. Your response to each question should be in the form of a report. Prepare the report in a word processor, integrating graphics and discussion. Print out and submit your report at the end of the test period. Only printed reports will be accepted. Electronic submissions will not be accepted.

1. In a study to see if remote sensing could determine the quality of a stand of trees, stands were observed by satellite and the "Band 5" satellite reading was recorded. The same stands were also observed on the ground, and the average height, the average diameter at breast height, and the crown cover index (that is, the percent of the ground covered by leaves when the stand is viewed from above) were recorded for each stand. Some stands had been damaged by wind or by cutting a road through the stand, and that was noted also. The quality of a stand is usually measured by the crown cover index, but mean height and diameter are also useful. Click here to get the data. Do an exploratory analysis of the data and explain what you have learned. [Hint: you might want to analyze the damaged and undamaged stands separately, or do comparative plots to compare damaged and undamaged.]
   
2. The file pcbinh20.html gives polychlorinated biphenyl (PCB) in water, ng/l, measured weekly from 1986-04-02 to 1996-03-28 in the Niagara River at Niagara on the Lake. Study the time sequence graphically, looking for the following features: trend, cyclic effects, change-points, autocorrelation. Does a log transformation make the data easier to interpret?

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Statistics 3N03