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(TCO 6) In the standard normal distribution, the standard deviation is always (Points: 5)0 1 2 none of these 2. (TCO 6) The area under a normal curve with mu = 8 and sigma = 3 is (Points: 5)0 1 2 none of these 3. (TCO 6) If John gets an 80 on a physics test where the mean is 85 and the standard deviation is 3, where does he stand in relation to his classmates? (Points: 5)He is in the top 5%. He is in the top 10%. He is in the bottom 5%. He is the bottom 1%. 4. (TCO 6) In a normal distribution with mu = 25 and sigma = 9, what number corresponds to z = -2? (Points: 5)21 16 7 none of these 5. (TCO 6) Let’s assume you have taken 100 samples of size 49 each from a normally distributed population. Calculate the standard deviation of the sample means if the population’s variance is 16. (Points: 5)0.571 0.429 0.327 0.107 6. (TCO 6) The area to the left of ‘z’ is 0.9192. What z-score corresponds to this area? (Points: 5)1.49 -1.49 1.40 none of these 7. (TCO 6) Find P(9 < x < 22) when mu = 20 and sigma = 5. (Points: 5)0.6554 0.6415 0.0139 0.3585 8. (TCO 7) What is the critical z-value that corresponds to a confidence level of 86%? (Points: 5)approximately 1.48 approximately 1.55 approximately 1.75 none of these 9. (TCO 7) Compute the population mean margin of error for a 99% confidence interval when sigma is 4 and the sample size is 36. (Points: 5)+/- 1.3066… +/- 1.0966... +/- 1.7166... none of these 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)16 27 26 none of these 11. (TCO 7) A private medical clinic wants to estimate the true mean annual income of its patients. The clinic needs to be within $100 of the true mean. The clinic estimates that the true population standard deviation is around $2,100. If the confidence level is 95%, find the required sample size in order to meet the desired accuracy. (Points: 10)1,695 2,100 1,432 1,700 12. (TCO 7) An auditor wants to estimate what proportion of a bank’s 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)550 610 601 580 (TCO 7) Interpret a 90% confidence interval of (4.355, 4.445) for a population mean. (Points: 10)2. (TCO 7) 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. (Points: 10)3. (TCO 7) An auditor wants to estimate what proportion of a bank’s commercial loan files are incomplete. The auditor randomly samples 80 files and finds 12 are incomplete. Using a 95% confidence interval, estimate the true proportion of incomplete files for ALL the bank’s commercial loans. Write a statement about the confidence level and the interval you find. (Points: 10)--------------------------------------------------------------------------------There are 2 pages in this exam. Be sure to complete all pages before submitting the exam.