# Probability and Statistics (3rd Edition)

## Corrections to the Solutions Manuals

### by Morris H. DeGroot and Mark J. Schervish

Some instructors may not want solutions posted on the web. I will only list which exercises have solutions that need to be corrected, together with some hints about how to correct the solutions.
• Section 1.4, Exercise 9(c). The C-n at the end should be Cn. (11/21/05)
• Section 1.9, Exercise 7. In the final expression, the first two multinomial coefficients form the numerator of the answer and the third one is the denominator. (11/21/05)
• Section 1.9, Exercise 11. The right-hand side of the second-to-last displayed equation should be the multinomial coefficient with n on top and n1,...,nk0+1 on the bottom. (11/21/05)
• Section 1.10, Exercise 1. The arithmetic in the final expression should have produced 0.1186 rather than 0.0388. (11/21/05)
• Section 2.2, Exercise 7(b). In the last line, both 0.6 should be 0.8 and the final answer is 0.8696, which is correct in the back of the textbook. (8/31/04)
• Section 2.3, Exercise 5. I missed a change of notation between writing the exercise and writing the solution. All of the Ai in the solution should be Bi and every B should be A. (8/31/04)
• Section 2.3, Exercise 8. In the commentary after the solution, the calculation in parentheses \$(0.95/0.05=19)\$ is actually the factor by which the odds in favor of the disease go up rather than the factor by which the probability of having the disease goes up. Because the odds were so small to start, the two factors are virtually the same. (9/21/05)
• Section 2.3, Exercise 16. In both tables i should run from 1 to 11 rather than 0 to 10. In the second table, the headings of the third and sixth columns should read "Example 2.3.11". (8/31/04)
• Section 3.1, Exercises 9 and 10. The solution labelled 9 is actually for Exercise 10. The series involved in the solution to Exercise 9 is one that students would not typically learn how to sum nowadays. They might have to look it up in a mathematical tables reference book. Instructors might wish to reword Exercise 9 to ask for a formula for c instead of the value. (8/31/04)
• Section 3.5, Exercise 8. In the fifth line, f(1/3,1/4)=4 should read f(1/3,1/4)=2. (8/31/04)
• Section 3.9, Exercises 17 and 18 (Instructor's Manual Only). The first two sentences of the solution to Exercise 17 were meant to be the first two sentences of the solution to Exercise 18. They refer to the typo mentioned for page 176 of the text. (8/31/04)
• Section 3.10, Exercise 6(b) and Exercise 7. Replace every instance of n2 by 2p in the solutions (page 91). Despite all this, the answer in the back of the text is correct for Exercise 7. (8/24/04)
• Section 5.7, Exercise 14. All of the 3's should be 2 instead. (12/1/05)
• Section 7.6, Exercise 9. As far as I can tell, the exercise was completely changed after the solution was written, and I forgot to rewrite the solutions. Sorry. The correct answer now appears on the corrections page for the text. (4/7/03)
• Section 8.1, Exercise 8. A 1/n appeared incorrectly in the solution, causing an erroneous factor of n1/2 to propogate throughout the solution. I hope that instructors will be able to recognize how to fix this. (5/1/03)
• Section 8.1, Exercise 11. The decimal place slipped one digit in one of the probabilities in part (a) of the solution and this carried over to part (b). There is also a correction to the answer on the corrections page for the text. (4/7/03)
• Section 9.7, Exercise 17. A minus sign was incorrectly written as a plus sign in the last equation of the solution. This affected the final answer, which has been noted on the corrections page for the text. (4/7/03)

View corrections to the text