STA218 Assignment 2

Quiz on Thursday Jan. 25 at the beginning of class

For this quiz, you will be allowed a single 8.5 by 11 one-sided formula sheet and a calculator. So write your formula sheet and use it to do the homework.

Read pages 38-43. You are responsible for the following concepts: Parameter, Statistic, Mean, Median, Mode, symmetric distribution, skewed left, skewed right. Do Exercises 2.24, 2.26a, 2.26b.

Read pages 45-51, and also Page 56 about the Coefficient of Variation. You are responsible for the following concepts, including the formulas: Range, MAD, Variance, Standard deviation, Coefficient of Variation. You arer not responsible for material that is being skipped. In particular, you are not reponsible for Tchebyshev's theorem, the empirical rule, or the trick in Swection 2.10 for estimating the standard deviation from the range. Any time you see references to these concepts in the text, ignore them. If any homework problem asks about these concepts, it's an oversight on my part.

Do Exercises 2.32a, 2.32b (use the formula from the definition as well as the computing formula), 2.34 (also verify MAD=1.2),

Read pages 69-72. You are responsible for percentiles and z-scores, and for the vocabulary "outlier." Later on, when we study the normal distributoin, I will explain why I disagee with the book's suggestion for identifying outliers. Do Exercises 2.54, 2.55, 2.57.

Here are some questions based on lecture:

1. Draw a rough picture of a positively skewed distribution. Which is bigger, the mean or the median?
2. Draw a rough picture of a negatively skewed distribution. Which is bigger, the mean or the median?
3. Which is a better measure of "average" income, the mean or the median? Why?
4. How long does the "average" automobile last? What kind of average do you think the manufacturer would report, and why?

Do the problems in preparation for the quiz. They are not to be handed in.