Chapter 9 Quiz.docx - Chapter 9 Quiz Subsection Question 1 2 2 points The mean number of travel days per year for salespeople employed by three hardware

# Chapter 9 Quiz.docx - Chapter 9 Quiz Subsection Question 1...

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Chapter 9 Quiz Subsection Question 1 2 / 2 points The mean number of travel days per year for salespeople employed by three hardware distributors needs to be estimated with a 0.90 degree of confidence. For a small pilot study, the mean was 150 days and the standard deviation was 14 days. If the population mean is estimated within two days, how many salespeople should be sampled? 133 452 511 2,100 Vie w Feedback Question 2 2 / 2 points There are 2,000 eligible voters in a precinct. A total of 500 voters are randomly selected and asked whether they plan to vote for the Democratic incumbent or the Republican challenger. Of the 500 surveyed, 350 said they would vote for the Democratic incumbent. Using the 0.99 confidence coefficient, what are the confidence limits for the proportion that plan to vote for the Democratic incumbent? 0.647 and 0.753 0.612 and 0.712 0.397 and 0.797 0.826 and 0.926 Vie w Feedback Question 3 2 / 2 points The mean weight of trucks traveling on a particular section of I-475 is not known. A state highway inspector needs an estimate of the population mean. He selects and weighs a random sample of 49 trucks and finds the mean weight is 15.8 tons. The population standard deviation is 3.8 tons. What is the 95% confidence interval for the population mean? 14.7 and 16.9 13.2 and 17.6 10.0 and 20.0 16.1 and 18.1 Vie w
Feedback Question 4 2 / 2 points Which of the following is a point estimate for the population mean (µ)? σ x/n x-bar s Vie w Feedback Question 5 2 / 2 points What is the interpretation of a 96% confidence level? There's a 96% chance that the given interval includes the true value of the population parameter. Approximately 96 out of 100 such intervals would include the true value of the population parameter. There's a 4% chance that the given interval does not include the true value of the population parameter. The interval contains 96% of all sample means. Vie w Feedback Question 6 2 / 2 points Which statement(s) is/are correct about the t distribution?

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