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1. (TCO 6) In the standard normal distribution, the variance is always (Points: 5) 2. (TCO 6) The area under the standard normal curve is (Points: 5) 3. (TCO 6) If Larry gets a 70 on a physics test where the mean is 65 and the standard deviation is 5.8, where does he stand in relation to his classmates? (Points: 5) 4. (TCO 6) In a normal distribution with mu = 25 and sigma = 3, what number corresponds to z = -3? (Points: 5) 5. (TCO 6) Letrsquos assume you have taken 100 samples of size 64 each from a normally distributed population. Calculate the standard deviation of the sample means if the populationrsquos variance is 49. (Points: 5) 6. (TCO 6) The area to the left of lsquozrsquo is 0.9192. What z-score corresponds to this area? 7. (TCO 6) Find P(9 lt x lt 15) when mu = 12 and sigma = 2. (Points: 5) 8. (TCO 7) What is the critical z-value that corresponds to a confidence level of 88%? (Points: 5) 9. (TCO 7) Compute the population mean margin of error for a 90% confidence interval when sigma is 4 and the sample size is 36. (Points: 5) 10. (TCO 7) A standard IQ test has a mean of 98 and a standard deviation of 16. We want to be 99% certain that we are within 8 IQ points of the true mean. Determine the sample size. (Points: 5) 11. (TCO 7) A private medical clinic wants to estimate the true mean annual income of its patients. The clinic needs to be within $200 of the true mean. The clinic estimates that the true population standard deviation is around $1,300. If the confidence level is 95%, find the required sample size in order to meet the desired accuracy. (Points: 10) 12. (TCO 7) An auditor wants to estimate what proportion of a bankrsquos commercial loan files are incomplete. The auditor wants to be within 4% of the true proportion when using a 95% confidence level. How many files must the auditor sample? No estimate of the proportion is available, so use 0.5 for the population proportion. (Points: 10) ESSAY QUESTIONS 1. Interpret a 95% confidence interval of (3.355, 3.445) for the population mean. 2. A nursing school wants to estimate the true mean annual income of its alumni. It randomly samples 200 of its alumni. The mean annual income was $55,200 with a standard deviation of $1,500. Find a 95% confidence interval for the true mean annual income of the nursing school alumni. Write a statement about the confidence level and the interval you find. lt!-- 393933939 --gt 3. An auditor wants to estimate what proportion of a bankrsquos commercial loan files are incomplete. The auditor randomly samples 60 files and finds 12 are incomplete. Using a 95% confidence interval, estimate the true proportion of incomplete files for ALL the bankrsquos commercial loans. Write a statement about the confidence level and the interval you find.


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