Typos in first printing of EP4A
Chapter 1
page 22, first proof: no dx in formula
page 27, line 3: the second 2 + 4 + 4 should be 2 + 2 + 6.
Chapter 2
Page 43: var (N ) + . . . E(N (N − 1)) + EN − (EN )2 , i.e., + not − in front of EN .
Page 43, Example 2.14: The number of trials is n = 16 . . . n − k = 13 failures.
Page 43, last equation (3/4)13 not (3/4)7
Problem 18. How many ways can eight rooks . . .
Problem 40. none of whom is currently busy.
Problem 59. from a group of 30
Chapter 3
Problem 51 is the same as 41
Chapter 5
Problem 23: Find the distribution of Y
Chapter 6
page 195, Theorem 6.1: X + Y = gamma(n + 1, λ)
page 195, proof: e−λ(z−x) → e−λ(z−x)
page 196, top: Y = gamma(n, λ)
page 201, hypergeometric distribution.
m m − 1 m 2
cov (X1 , X2 ) =
·
−
n n−1
n
The next line is correct as written.
Problem 21: will differ from 50 by 3 or fewer, that is, you will win if the difference is
4 or more. What is the probability he will win the bet?
Problem 41: gambler’s net winnings will be ≥ 0 after 100 bets.
Problem 48: 63%
Problem 50: A sample of 2089
Typos in the solutions to odd problems.
* indicates situations where the decimal was truncated rather than rounded creating
a difference of 1 in the last decimal place
1
Chapter 1
49. 22.666
Chapter 2.
21. (c) 50, 400
23. 50!/(8!7!35!)
29. 90/1024
37. (b) 0.3774*
59. 0.3685*
77. 6/32
Chapter 3.
5 (a) .4386* (c) .1053*
63 (a) 3/8
Chapter 5
1. c = 1/9.
11. (b) 1 −
√
3/2.
2