Quiz 5.1A AP Statistics

1. The probability of rolling two six-sided dice and having the sum on the two dice equal 7 is 16 . (a) Interpret this probability. (b) You roll two dice six times. Are you guaranteed to get a sum of 7 once? Explain. 2. To pass the time during a long drive, you and a friend are keeping track of the makes and models of cars that pass by in the other direction. At one point, you realize that among the last 20 cars, there hasn’t been a single Ford. (Currently, about 16% of cars sold in America are Fords). Your friend says, “The law of averages says that the next car is almost certain to be a Ford.” Explain to your friend what he doesn’t understand about probability. 3. A bag contains 10 equally-sized tags numbered 0 to 9. You reach in and, without looking, pick 3 tags without replacement. We want to use simulation to estimate the probability that the sum of the 3 numbers is at least 18. Describe the simulation procedure below, then use the random number table on the next page to carry out 10 trials of you simulation and estimate the probability. Mark on or above each line of the table so that someone can clearly follow your method. © 2011 BFW Publishers The Practice of Statistics, 4/e- Chapter 5 207 Random number table for question 3. 128 15689 14227 06565 14374 13352 49367 81982 87209 129 36759 58984 68288 22913 18638 54303 00795 08727 130 69051 64817 87174 09517 84534 06489 87201 97245 131 05007 16632 81194 14873 04197 85576 45195 96565 208 The Practice of Statistics, 4/e- Chapter 5 © 2011 BFW Publishers Quiz 5.1B AP Statistics Name: 1. The probability of flipping four coins and getting four “heads” is 1 16 . (a) Interpret this probability. (b) You flip four coins 32 times. Are you guaranteed to get four “heads” twice? Explain. 2. You are playing a board game with some friends in which each turn begins with rolling two dice. In this game, rolling “doubles”—the same number on both dice—is especially beneficial. You’ve rolled doubles on your last three turns, and one of your friends says, “No way you’ll roll doubles this time, it would be nearly impossible.” Explain to your friend what he doesn’t seem to understand about probability. 3. A school’s debate club has 10 members, 6 females and 4 males. If the team decides to pick two members randomly to participate in a debate, what is the probability that both of the chosen members are female? We want to use simulation to estimate this probability. Describe the simulation procedure below, then use the random number table on the next page to carry out 10 trials of your simulation and estimate the probability. Mark on or above each line of the table so that someone can clearly follow your method. © 2011 BFW Publishers The Practice of Statistics, 4/e- Chapter 5 209 Random number table for question 3. 141 96767 35964 23822 96012 94591 65194 50842 53372 142 72829 50232 97892 63408 77919 44575 24870 04178 143 88565 42628 17797 49376 61762 16953 88604 12724 144 62964 88145 83083 69453 46109 59505 69680 00900 210 The Practice of Statistics, 4/e- Chapter 5 © 2011 BFW Publishers Quiz 5.1C AP Statistics Name: 1. A couple has two sons and decide to have a third child. The husband says, “We’re bound to have a daughter this time: things balance out.” The wife says, “Nonsense! Two boys in a row means we are more likely to have another boy.” Comment on this disagreement, based on your understanding of probability. 2. The probability that a randomly selected person in the United States is left-handed is about 0.14. (a) Use this probability to explain what the Law of Large Numbers says. (b) Among the 28 students in Mr. Millar’s Calculus BC class, 8 are left-handed. Could this have happened by chance alone? Describe how you would use a random number table to simulate the proportion of left-handers in a class of 28 students if they were chosen randomly from a population that is 14% left-handed. Do not perform the simulation.