) In the standard normal distribution the means is always (Points : 3) 0 1 2 none of these 2. (TCO 6) The area under the standard normal curve is (Points : 3) 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 : 3) 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 = 6, what number corresponds to z = 3? (Points : 3) 40 43 46 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 : 3) 0.571 0.429 0.327 0.107 6. (TCO 6) The area to the left of ‘z’ is 0.0681. What z-score corresponds to this area? (Points : 3) -1.40 1.49 -1.49 none of these 7. (TCO 6) Find P(9 < x < 15) when mu = 12 and sigma = 2. (Points : 3) 0.9332 0.0668 0.8664 0.1336 8. (TCO 7) What is the critical z-value that corresponds to a confidence level of 92%? (Points : 3) 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 : 3) +/- 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 : 3) 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 $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 : 6) 205 163 200 150 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 10% 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 : 6) 90 97 105 180 (TCO 7) Interpret a 95% confidence interval of (3.355, 3.445) for the population mean. (Points : 6) 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 $52,500 with a standard deviation of $1,800. 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 : 6) 3. (TCO 7) An auditor wants to estimate what proportion of a bank’s 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 bank’s commercial loans. Write a statement about the confidence level and the interval you find. (Points : 6)