STATISTICS 3N03/3J04

TEST #1b * 2005-10-06
Instructions

This test is to be written in the BSB Student Technology Centre. 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 consult any of the web pages for this course and the SSC Case Study pages,
but you may not look at any other web pages, use e-mail or communicate with anyone else.

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.

Question 1

Do an exploratory graphical analysis of the data in the Niagara River Pollution Case Study. Specifically,

  1. Use box plots to compare PCB in Solids at Fort Erie with PCB in Solids at Niagara on the Lake.
  2. Plot PCB in Solids against Julian date, with separate traces for Fort Erie and Niagara on the Lake superimposed on the same graph.
  3. Repeat (b), this time applying exponential smoothing to the series.
  4. The objective of the study was to see if the amount of pollution enering the Niagara River between Fort Erie and Niagara on the Lake had decreased during the 20-year period. Which of the above graphs help to answer this question? Would log transformations make this any clearer? [Note: Niagara on the Lake is downstream from Fort Erie.]
  5. Does the concentration of Dieldrin in water at Fort Erie follow a Normal distribution? Does the log concentration?

Question 2

The following data show the current necessary to achieve a certain level of brightness in a television tube, for two different types of glass and three different types of phosphor. Analyse the data graphically.

PHOSPHOR
1 2 3
GLASS 1 280, 290, 285 300, 310, 295 270, 285, 290
2 230, 235, 240 260, 240, 235 220, 225, 230

Question 3

Give three interesting facts about John Tukey.

Statistics 3N03/3J04