This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Charles M. Grinstead and J. Laurie Snell: INTRODUCTION to PROBABILITY Published by AMS Solutions to the exercises SECTION 1.1 1. As n increases, the proportion of heads gets closer to 1/2, but the diference between the number of heads and half the number of ips tends to increase (although it will occasionally be 0). 3. (b) If one simulates a suFciently large number of rolls, one should be able to conclude that the gamblers were correct. 5. The smallest n should be about 150. 7. The graph of winnings for betting on a color is much smoother (i.e. has smaller uctuations) than the graph for betting on a number. 9. Each time you win, you either win an amount that you have already lost or one of the original numbers 1,2,3,4, and hence your net winning is just the sum of these four numbers. This is not a foolproof system, since you may reach a point where you have to bet more money than you have. If you and the bank had unlimited resources it would be foolproof. 11. or two tosses, the probabilities that Peter wins 0 and 2 are 1/2 and 1/4, respectively. or four tosses, the probabilities that Peter wins 0, 2, and 4 are 3/8, 1/4, and 1/16, respectively. 13. Your simulation should result in about 25 days in a year having more than 60 percent boys in the large hospital and about 55 days in a year having more than 60 percent boys in the small hospital. 15. In about 25 percent of the games the player will have a streak of ve. SECTION 1.2 1. P ( { a, b, c } ) = 1 P ( { a } ) = 1 / 2 P ( { a, b } ) = 5 / 6 P ( { b } ) = 1 / 3 P ( { b, c } ) = 1 / 2 P ( { c } ) = 1 / 6 P ( { a, c } ) = 2 / 3 P ( ) = 0 3. (b), (d) 5. (a) 1/2 (b) 1/4 (c) 3/8 (d) 7/8 7. 11/12 9. 3 / 4 , 1 11. 1 : 12 , 1 : 3 , 1 : 35 13. 11:4 15. Let the sample space be: 1 = { A, A } 4 = { B, A } 7 = { C, A } 1 2 = { A, B } 5 = { B, B } 8 = { C, B } 3 = { A, C } 6 = { B, C } 9 = { C, C } where the rst grade is Johns and the second is Marys. You are given that P ( 4 ) + P ( 5 ) + P ( 6 ) = . 3 , P ( 2 ) + P ( 5 ) + P ( 8 ) = . 4 , P ( 5 ) + P ( 6 ) + P ( 8 ) = . 1 . Adding the rst two equations and subtracting the third, we obtain the desired probability as P ( 2 ) + P ( 4 ) + P ( 5 ) = . 6 . 17. The sample space for a sequence of m experiments is the set of mtuples of S s and F s, where S represents a success and F a failure. The probability assigned to a sample point with k successes and mk failures is 1 n k n1 n mk . (a) Let k = 0 in the above expression. (b) If m = n log 2, then lim n 11 n m = lim n 11 n n log 2 = lim n ( 11 n n log 2 = e1 log 2 = 1 2 ....
View
Full
Document
This note was uploaded on 04/08/2008 for the course ENGR 2350 taught by Professor Borzova during the Spring '08 term at SMU.
 Spring '08
 BORZOVA

Click to edit the document details