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Question: nclass exercise 1 instructions submit your work through blackboard by...

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n-Class Exercise 1 Instructions: Submit your work through Blackboard by the due date. Late submissions are not allowed. You can take photos of or scan your solutions Calculate or write the formulas for each test statistic and p-value for each hypothesis test question (questions 7-10). It is true you will never have to calculate these in real life, however, you should know what Megastat, or any other statistical software, is calculating. 1) According to an IRS study, it takes a mean of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. This distribution of times follows the normal distribution and the standard deviation is 80 minutes. A consumer watchdog agency selects a random sample of 40 taxpayers. a) What is the standard error of the mean in this example? b) What is the likelihood the sample mean is greater than 320 minutes? c) What is the likelihood the sample mean is greater than 350 minutes? 99 Words English (US
2) A sample of 250 observations is selected from a normal population for which the population standard deviation is known to be 25. The sample mean is 20 a. Determine the standard error of the mean. b. Determine the 95% confidence interval for the population mean. 3) Suppose you know ơ and you want an 85% confidence level. What is the critical value? 4) The owner of Brittens Egg Farm wants to estimate the mean number of eggs produced per chicken. A sample of 20 chickens shows they produced an average of 20 eggs per month with a standard deviation of 2 eggs per month. a. Explain why we need to use the t distribution. b. Develop the 95% confidence interval for the population mean. c Would it be reasonable to conclude that the population mean is 21 eggs? What about 25 eges?
5) The owner of the West End Kwick Fill Gas Station wishes to determine the proportion of customers who use a credit card or debit card to pay at the pump. He surveys 100 customers and finds that 80 paid at the pump. a. Estimate the value of the population proportion. b. Develop a 95% confidence interval for the population proportion. c. Interpret your findings.
6) Ms. Maria Wilson is considering running for mayor of the town of Bear Gulch, Montana. Before completing the petitions, she decides to conduct a survey of voters in Bear Gulch. A sample of 400 voters reveals that 300 would support her in the November election a. Estimate the value of the population proportion b. Develop a 99% confidence interval for the population proportion. c Interpret your findings Ee ,-- □ Focus
7) Very satisfied customers give the XYZ-Box video game system a rating that is at least 42. Suppose that the manufacturer of the XYZ-Box wishes to use the 65 satisfaction ratings to provide evidence supporting the claim that the mean composite satisfaction rating for the XYZ- Box exceeds 42. Their random sample of 65 satisfaction ratings yields a sample mean ofi42.954. Assuminthat σ=2.64, is the XYZ-Box video game systems mean composite rating greater than 42?
8) An automobile parts supplier owns a machine that produces a cylindrical engine part. This part is supposed to have an outside diameter of 3 inches. Parts with diameters that are too small or too large do not meet customer requirements and must be rejected. To verify that parts meet customer requirements, a special study randomly samples 40 parts produced by the machine. The sample of 40 parts yields a sample mean, 3.006 inches. Assume σ 0.016. If the results show that the mean diameter does not equal the target value of 3 inches, the company will assign a problem-solving team to intensively search for the causes of the problem. Should the problem solving team be assigned? 昂ほー□ Focus
9) The bad debt ratio for a financial institution is defined to be the dollar value of loans defaulted divided by the total dollar value of all loans made. Suppose that a random sample of seven Ohio banks is selected and that the bad debt ratios (written in percentages) for these banks are 796, 4%, 6%, 7%, 5%, 4%, and mean bad debt ratio for all Midwestern banks is 7% and that the mean debt ratio for Ohio banks is lower. Is this correct claim? 9%. Banking officials claim that the E English (US
10) Suppose a national survey finds that 73% of restaurant employees say that work stress has a negative impact on their personal lives. A random sample of 200 employees of large restaurant chain finds that 141 employees say that work stress has a negative impact on their personal lives. Is there enough evidence to show that the percentage of work stress employees for the restaurant chain differs from the national percentage? Test this hypothesis atthe α-0.0S level. REFocus 100%
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