Chapters 5 and 6 Quiz 1. Joe has been given a 10 multiple-choice question in his Geography class. Each question has 5 answers, of which only one is correct. Since Joe has not studied for the quiz, he plans in guessing all of the answers. What is the probability that he answers at least one question correctly? a) 0.107 b) 0.500 c) 0.893 d) 0.656 2. A stationary store has decided to accept a large shipment of ball-point pens if an inspection of 20 randomly selected pens yields no more than two defective pens. Find the probability that the shipment is accepted if 5% of the total shipment is defective? a) 0.924 b) 0.076 c) 0.050 d) 0.025 3. An experiment consists of rolling a fair die 8 times and recording the number of times a 3 occurs? The usual number of times a 3 occurs is: a) 1, 2 and 3. b) 0, 1, and 2. c) 0, 1, 2, and 3. d) 2 and 3 only. 4. Sample items are popular in supermarkets. Costumer take free samples in about 60% of the cases. When 317 costumers are observed, what is the probability that more than 180 will take a sample? a) 0.8790 b) 0.8665 c) 0.1335 d) 0.1210 5. Coal is carried from mines to power plants in hopper cars on a long train. Weights of coal loaded into a car are normally distributed with mean 75 tons and standard deviation 0.8 tons. What is the probability that 20 cars chosen at random will have a mean load weight of less than 74.5 tons of coal? a) 0.2643 b) 0.0026 c) 0.7357 d) 0.3564 c) 0. 2367 d) 0.8699 6. What is P( -1.23 < z <2.03)? a) 0.9788 b) 0.1093 7. What percentage of adults have an IQ score between 85 and 125 points? Assume that IQ scores are normally distributed with a mean 100 points and a standard deviation 15 points. a) 0.7938 b) 0.9525 c) 0.1587 d) 0.9500 Consider the following experiment: \" Rolling a pair of fair dice 10 times and recording the number of times we get a 7\". 8. One of the following statements is not true. a) A fixed number of trials, 10 b) The probability of rolling a 7 is 1/6 for every trial. c) There are several possible outcomes. d) Each trial is independent. 9. The probability of rolling exactly 3 sevens is: a) 0.8450 b) 0.8965 c) 0.1550 d) 01035 10. The probability of rolling at least 1 seven. a) 0.8385 b) 0.1615 c) 0.0985 d) 0.9015