ortation daily (USA Today,  December 21, 2005). a. In a sample of 10 workers, what is the probability that exactly three workers take public  transportation daily? b. In a sample of 10 workers, what is the probability that at

According to the 2016 National Survey on Drug Use and Health, 6.5% of teenagers aged 12-17 used marijuana. Suppose that 1,500 teenagers aged 12-17 are chosen at random, what is the expected number of cannabis users among those selected? What is the standard deviation of the number of cannabis users?

5. The ages of U.S. commercial aircraft have a mean of 13 years and a standard deviation of 7.9 years (based on data from Aviation Data Services). a. If the Federal Aviation Administration randomly selects 35 commercial aircraft for special stress tests, find the probability that the mean age of this sample group is greater than 15 years? b. If the Federal Aviation Administration randomly selects 42 commercial aircraft for special stress tests, what is the mean sample age of the aircraft for the top 75% of the sample?4

a)  What is the smallest group Alice can counsel to be at least 98% sure that three or more parolees will not become repeat offenders? b) What is the standard deviation? (Round your answer to two decimal places.)  parolees

7) $40,000, with a standard deviation of $2000. Assuming that the distribution of income is (approximately) normal, what is the probability that a worker picked at random will have the annual income between $39,000 and $42,000 ? The mean annual income of a worker in a certain professional category is

1. Most graduate schools of business require applicants for admission to take the Graduate Management Admission Council's GMAT examination. Scores on the GMAT are roughly normally distributed with a mean of 527 and a standard deviation of 112. a. What is the probability of an individual scoring above 500 on the GMAT? b. How high must an individual score on the GMAT in order to score in the highest 5%? a. 0.5948 a. 0.2348 a. 0.4269 b.x=711.24 b. x=700.21 b. x=721.24

3. A sociologist will conduct a two-sample t-test for a difference in means to investigate whether there is a significant difference, on average, between the salaries of people with bachelor's degrees and people with master's degrees. From a random sample of 32 people with a bachelor’s degree, the average salary was $55,000 with standard deviation $3,500. From a random sample of 28 people with a master's degree, the average salary was $58,000 with a standard deviation of $4,000. With a null hypothesis of no difference in the means, which of the following is the test statistic for the appropriate test to investigate whether there is a difference in population means (master's degree minus bachelor's degree) ? (58,000–55,000) A 3,500 + 28 4,000 32 (58,000–55,000) B 4,0002 3,5002 28 32 (58,000–55,000) t = 3,5002 + 28 4,0002 32 (58,000–55,000) | 4,000+3,500 28+32 (58,000–55,000) t E | 4,0002 +3,5002 28+32