Question

Hello, I'm doing some midterm review and am having trouble understanding these questions, could you walk me through how to solve for these step by step so I can follow along and learn from how they were completed?

Thanks in advance!

This information comes from Essentials of Statistics for Business and Economics 8th edition 1 Based on exercise 17 from chapter 6 in the textbook. The mean cost of domestic airfares rose to an all-time high of $385 per ticket Airfares were based on the total ticket value, which consisted of the price charged by the airlines plus any additional taxes and fees. Assume domestic airfares are Normally distributed with a standard deviation of $110. a) What is the probability that a domestic airfare is $550 or more? b) What is the probability that a domestic airfare is $250 or less? c) What is the probability that a domestic airfare is between $300 and $500 d) What is the cost for the 3% highest domestic airfares? Based on exercise 24 from chapter 7 in the textbook. The average number of weeks an individual is unemployed is 17.5 weeks. Assume that for the population of all unemployed individuals the population mean length of unemployment is 175 weeks and that the population standard deviation is 4 weeks. Suppose you would like to select a sample of 50 unemployed individuals for a follow up study a) What are the mean and standard deviation of the sampling distribution of x? b) What is the probability that a simple random sample of 50 unemployed individuals will provide a sample mean within 1 week of the population mean? c) What has to be the value of so that it is in the top 10% of sample mean values? 3. Based on exercise 35 from chapter 7 in the textbook. A company believes that 30% of the firm's orders come from first-time customers. A random sample of 100 orders will be used to estimate the proportion of first time customers a) Assume that the president is correct and p=0.30. What is the sampling distribution of for this study? b) What is the probability that the sample proportion will be between 0.20 and 0.40?

Answer 1

solution :- 4 = 385 22 = xull} OJ PLX2550) = P1Z2 550-385) l=385 = 110 = 1- P(241.50) = Plaz 1.50) = 10.0668 11o b) P(x(250) = P12=250-385) = P124-1.23) = 0.1093 C) P( 300 CXL 500) -Pr 300-385 cal 500-3851 10 110 = P(-0.77 (22105) = 0.6325 d) for highest 3% of Score z-score = 1.88 Now, Z = x-4 110 =) 1.88 = x-385 => x = 5927 S9