Time: 20 minutes. This quiz is closed book, closed notes, no calculator.
The following questions ask you to draw Q-Q plots. In every case, let the X axis show the values of the "reference distribution" (or very large batch of data) and the Y axis show the values of a batch of data. The reference distribution is the standard Normal distribution N(0,1) whose PDF is proportional to exp(-x2/2).
1. Sketch a Q-Q plot showing a batch that has longer tails (high and low) than the reference distribution.
2. Sketch a Q-Q plot for a batch that has one extremely low outlier and one extremely high outlier.
3. Sketch a Q-Q plot, as accurately as possible (show scales on the axes), where the batch has a shape essentially identical to the reference distribution but has one-third the spread.
4. Sketch a Q-Q plot, as accurately as possible (show values on the axes), where the batch consists of a large number of values drawn from a Normal distribution with mean 17 and standard deviation 1 (N(17, 1)).
5. Sketch a Q-Q plot showing a very negatively skewed batch.
6. Compute (to one decimal place), showing your work:
a) ln(8)
b) ln(200)
c) log2(1/4)
d) ln(-e)
e) ln(exp(17))
Scoring: The passing score is 92.
Return to the Environmental Statistics home page
This page is copyright (c) 2001 Quantitative Decisions. Please cite it as
This page was created 18 February 2001.