This test is to be written in the BSB Computer Lab. You may use any software in the course folder, but you may not import any files on floppy disk or from the network. Other aids permitted: any calculators and one sheet of notes (8.5" x 11", one side only).

The data sets will be found in the folder Test #1 on the STAT3N03 course folder.

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. The contact resistance of a break-only relay was studied for three different materials, all of them silver-based alloys. Thirty measurements were made, about 10 with each alloy. The file alloy.txt gives the results. What can you say about the effect of the different alloys on contact resistance?
   
2. The file pcb_in_solids.txt gives polychlorinated biphenyl (PCB) in suspended solids, ng/g, measured weekly from 1986-04-02 to 1996-03-28 in the Niagara River at Fort Erie. Missing values are denoted by "*". 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?
   
3. The file sweat.txt gives measurements of sweat rate, sodium content and potassium content for 20 healthy females undergoing a standardized exercise program. Discuss any relationships you can find between these variables. Do any of the variables seem to follow normal distributions?
   
4. What is the probability of getting a twelve (i.e. two sixes) when a pair of fair dice are rolled? Let X be the number of times a twelve is obtained when a pair of dice are rolled 72 times. What is the probability distribution of X? Plot an accurate graph of this probability distribution.

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Statistics 3N03