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qHide Question 1 4 points A study of 200 apple trees showed that the average number of apples per tree was 500. The standard deviation of the population is 200. Which of the following is the 98% confidence interval for the mean number of apples for all trees? Save (472.3, 527.7) (467.1, 532.9) (463.8, 536.2) (463.6, 536.4) Question 2 4 points A study of 50 white mice showed that their average weight was 6.2 ounces. The standard deviation of the population is 0.4 ounces. Which of the following is the 90% confidence interval for the mean weight per white mouse? Save (6.11, 6.29) (5.98, 6.42) (6.09, 6.31) (5.54, 6.86) Question 3 4 points A study of 90 bolts of carpet showed that their average length was 200 yards. The standard deviation of the population is 6 yards. Which of the following is the 95% confidence interval for the mean length per bolt of carpet? Save (198.96, 201.04) (197.06, 202.94) (198.53, 201.47) (198.76, 201.24) Question 4 4 points If a population has standard deviation 14, what is the minimum sample size to be 95% confident that the error should be accurate to within 5? Save 61 6 31 12 Question 5 4 points A researcher conducted a study of the access speed of 30 hard drives and concluded that his maximum error of estimate was 20. If he were to conduct a second study to reduce the maximum error of estimate to 4, about how many hard drives should he include in his new sample? Save 30 60 150 750 Question 6 4 points A study of peach trees showed that the average number of peaches per tree was 500. The standard deviation of the population is 200. A scientist wishes to find the 95% confidence interval for the mean number of peaches per tree. How many trees does she need to sample to be accurate within 14 peaches per tree? Save 205 553 658 784 Question 7 4 points A study of elephants wishes to determine the average weight of a certain subspecies of elephants. The standard deviation of the population is 1500 pounds. How many elephants need to be weighed so find we can be 90% confident to be accurate within 350 pounds? 50 60 71 Save 166 Question 8 4 points A previous study of nickels showed that the standard deviation of the weight of nickels is 200 milligrams. A coin counter manufacturer wishes to find the 80% confidence interval for the average weight of a nickel. How many nickels does he need to weigh to be accurate within 10 milligrams? Save 400 657 1083 284 Question 9 4 points A previous analysis of paper boxes showed that the standard deviation of their lengths is 7 millimeters. A packer wishes to find the 99% confidence interval for the average length of a box. How many boxes does he need to measure to be accurate within 4 millimeters? Save 4 30 21 17 Question 10 4 points Save In a study of size 8 where the variance is unknown, the distribution that should be used to calculate confidence intervals is a normal distribution a t distribution with 7 degrees of freedom a t distribution with 8 degrees of freedom a t distribution with 9 degrees of freedom Question 11 4 points A food snack manufacturer samples 13 bags of pretzels off the assembly line and weighed their contents. If the sample mean is 9.8 and the sample standard deviation is 0.15, find the 95% confidence interval of the true mean. Save (9.76, 9.84) (9.47, 10.13) (9.72, 9.88) (9.71, 9.89) Question 12 4 points 8 squirrels were found to have an average weight of 9.8 ounces with a sample standard deviation is 0.10. Find the 95% confidence interval of the true mean weight. Save (9.69, 9.91) (9.48, 10.12) (9.71, 9.89) (9.76, 9.84) Question 13 4 points The winning team's scores in 7 high school basketball games were recorded. If the sample mean is 10.2 points and the sample standard deviation is 0.25 points, find the 98% confidence interval of the true mean. Save (10.11, 10.29) (9.90, 10.50) (9.98, 10.42) (9.61, 10.79) Question 14 4 points A recent study of 750 Internet users in Europe found that 35% of Internet users were women. What is the 95% confidence interval of the true proportion of women in Europe who use the Internet? Save 0.321<p<0.379 0.316<p<0.384 0.309<p<0.391 0.305<p<0.395 Question 15 4 points A survey of 800 women shoppers found that 17% of them shop on impulse. What is the 98% confidence interval for the true Save proportion of women shoppers who shop on impulse? 0.148<p<0.192 0.136<p<0.204 0.144<p<0.196 0.139<p<0.201 Question 16 4 points A random sample of 70 voters found that 40% were going to vote for a certain candidate. Find the 95% limit for the population proportion of voters who will vote for that candidate. Save 28.5% < p < 51.5% 29.4% < p < 50.6% 30.4% < p < 49.6% 34.3% < p < 45.7% Question 17 4 points A random sample of 95 printers discovered that 15 of them were being used in small businesses . Find the 99% limit for the population proportion of printers that are used in small businesses. Save -0.026 < p < 0.341 0.062 < p < 0.254 0.071 < p < 0.245 0.126 < p < 0.190 Question 18 4 points In a sample of 60 mice, a biologist found that 42% were able to run a maze in 30 seconds or less. Find the 95% limit for the population proportion of mice who can run that maze in 30 seconds or less. Save 35.8% < p < 48.2% 31.5% < p < 52.5% 29.5% < p < 54.5% 23.3% < p < 60.7% Question 19 4 points Save In a sample of 855 bartenders, 48% heard complaints from patrons about work. If the margin of error was 4.4%, what was the confidence level that was used? 90% 95% 98% 99% Question 20 4 points A recent poll of 700 people who work indoors found that 278 of them smoke. If the researchers want to be 98% confident of their results to within 3.5%, how large a sample is necessary? Save 751 1062 1301 532 Question 21 4 points The Academy of Orthopedic Surgeons states that 80% of women wear shoes that are too small for their feet. A researcher wants to be 98% confident that this proportion is within 3% of the true proportion. How large a sample is necessary? Save 966 683 1183 484 Question 22 4 points A report states that 40% of home owners had a vegetable garden. How large a sample is needed to estimate the true proportion of home owners who have vegetable gardens to within 6% with 95% confidence? 65 129 257 Save 514 Question 23 4 points A report states that 42% of home owners had a vegetable garden. How large a sample is needed to estimate the true proportion of home owners who have vegetable gardens to within 5% with 96% confidence? Save 121 206 242 411 Question 24 4 points A sample of 1,108 was used to estimate a proportion with 98% confidence. If , what was the amount of error? Save 0.040 0.025 0.035 0.028 Question 25 4 points John Davis, a manager of a supermarket, wants to estimate the proportion of customers that will be using food stamps at his store. How large a sample is required to estimate the true proportion to within 3% with 98% confidence? 756 1,849 1,067 1,509 1 _3993545_1 _3993545_1 Save