Homework answers / question archive / Name ______________________ Business Statistics Free Response Questions #5: for Chapters 8 and 9 Worth 10 points

Name ______________________ Business Statistics Free Response Questions #5: for Chapters 8 and 9 Worth 10 points

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Name ______________________ Business Statistics Free Response Questions #5: for Chapters 8 and 9 Worth 10 points. Directions: You can either type out answers to these questions then submit a word document or pdf (please no GoogleDoc sharing links or Apple pages files) or you can write out your answer by hand and take a photo (try to avoid HEIC image format, please) or scan the sheet of paper. PLEASE make sure you hand in something that is aligned correctly (not sideways) and clear enough for me to read. 1. A bus company is interested in the opinions of their frequent riding customers about their proposed new bus routes. Specifically, they want to know what proportion of them plan to use one of their new hubs in the next year. They take a random sample of 1,000 from the database of all frequent riders and send them an e-mail message with a request to fill out a survey in exchange for free bus tickets. a) What is the population? b) What is the sampling frame? c) What is the population parameter of interest? d) What sampling method is used? 2. Examine each of the following questions for possible bias. If you think the question is biased, indicate how and propose a better question. Explain your answers. a) Do you think that price or quality is more important in selecting a tablet computer? b) Given humanity's great tradition of exploration, do you favor continued funding for space flights? 3. A market researcher for a provider of iPhone accessories wants to know the proportion of customers who own cars to assess the market for a new iPhone car charger. A sample of 400 customers indicates that 72% own cars. SHOW WORK. a) What is the standard error of the sampling distribution of the proportion? b) How large would the standard error have been if he had surveyed only 100 customers (assuming the proportion is about the same)? 4. From a survey of coworkers you find that 48% of 200 have already received this year's flu vaccine. An approximate 95% confidence interval is (0.409,0.551). For the following, would the confidence interval be wider or narrower and explain why. a) How would the confidence interval change if the sample size had been 800 instead of 200? Why? b) How would the confidence interval change if the confidence level had been 90% instead of 95%? Why? c) How would the confidence interval change if the confidence level had been 99% instead of 95%? Why? 5. Advertisers. Direct mail advertisers send solicitations (“junk mail”) to thousands of potential customers in the hope that some will buy the company's product. The response rate is usually quite low. Suppose a company wants to test the response to a new flyer and sends it to 1000 people randomly selected from their mailing list of over 200,000 people. They get orders from 123 of the recipients. a) Create a 90% confidence interval for the percentage of people the company contacts who may buy something. Give x, n, and p-hat for this as well as the StatCrunch output. **Make sure you provide images or screenshots of your StatCrunch output, you will lose points if you don’t. b) b) Explain what this interval means. c) The company must decide whether to now do a mass mailing. The mailing won't be cost-effective unless it produces at least a 5% return. What does your confidence interval suggest? Explain