Focus Exercises

Note: the Exercises in the text are listed with two digits, the first being the Chapter number;
for example, Chapter 1 Exercise 4 below is Exercise 1.4 in the text.

Chapter 1	4, 8, 12, 16, 17
Chapter 2	8, 19
Chapter 3	6, 12, 15, 24
Chapter 4	4, 10, 23
Chapter 5	3, 7, 12, 18
Chapter 6	4, 8, 18(b)
Chapter 7	10, 25
Chapter 8	4, 6
Chapter 9	3, 9, 13, 17, 21, 27
Chapter 10	6, 10, 14, 19
Chapter 11	6, 7, 17, 18
Chapter 12	8, 12, 13, 18
Chapter 13	12, 14, 22, 24, 26, 30
Chapter 14	8, 12, 23, 26
Chapter 15	11, 18, 24, 30, 32
Chapter 16	4, 12 (Omit these)
Chapter 17	8, 22
Chapter 18	4, 8, 20
Chapter 19	7, 12
Chapter 20	10, 12, 15
Chapter 21A	4, 7, 8, 16, 21, 22
Chapter 21B	29, 30, 32
Chapter 22A	4, 6, 12, 14, 20, 24, 25
Chapter 22B	29, 30, 32, Question below
Chapter 23	3, 5, 11, 13 (Omit these)
Chapter 24	Question below

Chapter 22B extra question: In Exercises 21.32 and 22.32, you carried out the calculations for a confidence interval and test based on a bank’s experiment in changing the rules for its credit cards. You ought to ask some questions about this study.
(a) The distribution of the amount charged is skewed to the right, but outliers are prevented by the credit limit that the bank enforces on each card. Why can we use a test and confidence interval based on a normal sampling distribution for the sample mean "x-bar"?
(b) The bank’s experiment was not comparative. The increase in amount charged over last year may be explained by lurking variables rather than by the rule change. What are some plausible reasons why charges might go up? Outline the design of a comparative randomized experiment to answer the bank’s question.

Chapter 24 question: Results from a study of the relationship between gender (Male/Female) and drunk driving (Yes/No) yielded a chi-squared value of 1.637 from a 2x2 table. Is this significant evidence of a relationship between these two variables? Explain.