Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Name: _______________________ Chapter 9 Quiz AP Statistics 1.) Which of the following are true statements? I. The larger the sample, the larger the spread in the sampling distribution. II. Provided that the population size is significantly greater than the sample size, the spread of a sampling distribution is about the same no matter what the population size. III. Bias has to do with the center, not the spread, of a sampling distribution. (A) I and II (D) I, II, and III (B) I and III (C) II and III (E) None of the above. 2.) Which of the histograms represents the sampling distribution of p for p = 0.7 and n = 84? (A) (B) (D) (C) (E) 3.) The distribution of weights of “16 ounce” potato chip bags is given by the histogram on the right: The distribution has a mean of 16.96 ounces with a standard deviation of 2.31 ounces. If 50 random samples of 12 bags each are picked, and the mean weight of each sample is found, which of the following is most likely to represent the distribution of the sample means? (A) (D) (B) (C) (E) None of the above. High school dropouts make up 14.1% of all Americans aged 18 to 24. A vocational school that wants to attract dropouts mails an advertising flyer to 25,000 persons between the ages of 18 and 24. 4.) If the mailing list can be considered a random sample of the population, what is the mean number of high school dropouts who will receive the flyer? 5.) Find the standard deviation for the number of dropouts. (Be careful.) 6.) Is the population of dropouts normally distributed? Can you assume the sampling distribution is normally distributed? Explain. 7.) What is the probability that at least 3500 dropouts will receive the flyer? (Include a sketch as part of your computation.) 8.) What is the probability that between 3000 and 6000 dropouts will receive the flyer? The weight of chocolate bars is approximately normally distributed with a mean of 8 ounces and a standard deviation of 1.2 ounces. 9.) What is the probability that a randomly chosen chocolate bar weighs 10 ounces or more? 10.) What are the mean and standard deviation of the average chocolate bar weight x for an SRS of 32 bars? 11.) What is the probability that the average chocolate bar weight of an SRS of 32 bars is 10 ounces or higher? 12.) Would your answers to 9, 10, or 11 be affected if the distribution of chocolate bar weights in the population were distinctly nonnormal. Explain. 13.) Suppose that you and your lab partner flip a coin 20 times and you calculate the proportion of tails to be 0.7. Your partner seems surprised at these results and suspects that the coin is not fair. Write a brief statement that describes why you either agree or disagree with your partner. Be sure to provide support relating to the principles we have discussed in Chapter 9. 14.) SAT Math scores are normally distributed with a mean of 500 and a standard deviation of 100. If a random sample of 100 students had a mean SAT Math score of 525, would you describe these results as exceptional? Explain your answer. 15.) Children in kindergarten are sometimes given the Ravin Progressive Matrices Test (RPMT) to assess their readiness for learning. Experiences at Southwark Elementary School suggest that the RPMT scores for its kindergarten pupils have mean 13.6 and standard deviation 3.1. The distribution is close to normal. Mr. Lavin has 22 children in his kindergarten class this year. He suspects that their RPMT scores will be unusually low because the test was interrupted by a fire drill. To check this suspicion, he wants to find the level L such that there is probability only 0.05 that the mean score of 22 children falls below L when the usual Southwark distribution remains true. What is the value of L? A MLB scout is checking out a minor league pitching prospect and, using a timer, finds the average speed of his fastball to be 92.3 mph with a standard deviation of 2.3mph. Assume the pitcher never tires and there is a consistent normal distribution of fastball speeds. 16.) Would you check the timer if it registered 95 mph on the fastball? Explain. 17.) Would you check the timer if the next 30 fastballs averaged 95 mph?