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Week 6 Math 225n Statistics Questions and Answers 100% Assured Success. Chamberlain College of Nursing

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Download Week 6 Math 225n Statistics Questions and Answers 100% Assured Success. Chamberlain Colleg and more Exams Nursing in PDF only on Docsity! That is correct! That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) Question 1 A statistics professor recently graded final exams for students in her introductory statistics course. In a review of her grading, she found the mean score out of 100 points was a x¯=77, with a margin of error of 10. Construct a confidence interval for the mean score (out of 100 points) on the final exam. Answer: (67, 87) Question 2 A random sample of adults were asked whether they prefer reading an e-book over a printed book. The survey resulted in a sample proportion of p′=0.14, with a sampling standard deviation of σp′=0.02, who preferred reading an e-book. Use the empirical rule to construct a 95% confidence interval for the true proportion of adults who prefer e- books. Answer: ( 0.10, 0.18) Question 3 The pages per book in a library are normally distributed with an unknown population mean. A random sample of books is taken and results in a 95% confidence interval of (237,293) pages. What is the correct interpretation of the 95% confidence interval? Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) We estimate with 95% confidence that the sample mean is between 237 and 293 pages. We estimate that 95% of the time a book is selected, there will be between 237 and 293 pages. We estimate with 95% confidence that the true population mean is between 237 and 293 pages. Question 4 The population standard deviation for the heights of dogs, in inches, in a city is 3.7 inches. If we want to be 95% confident that the sample mean is within 2 inches of the true population mean, what is the minimum sample size that can be taken? Round up to the nearest integer. Answer: 14 dog heights Question 5 Clarence wants to estimate the percentage of students who live more than three miles from the school. He wants to create a 98% confidence interval which has an error bound of at most 4%. How many students should be polled to create the confidence interval? z0.10 z0.05 z0.02 5 z 0.01 z 0.005 1. 2 8 1.64 1.96 2.32 2.57 Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) two decimal places and use increasing order. 13.9 16.4 12.3 13.2 8.4 4.4 10.3 8.8 4.8 HelpCopy to ClipboardDownload CSV Answer: (9.22, 11.61) Question 8 Eric is studying people's typing habits. He surveyed 525 people and asked whether they leave one space or two spaces after a period when typing. 440 people responded that they leave one space. Create a 90% confidence interval for the proportion of people who leave one space after a period. • Round your results to four decimal places. Answer: (0.8117, 0.8645) Question 9 Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) A sample of 27 employees for the Department of Health and Human Services has the following salaries, in thousands of dollars. Assuming normality, use Excel to find the 98% confidence interval for the true mean salary, in thousands of dollars. Round your answers to two decimal places and use increasing order. 71 70 69 65 72 69 72 72 71 HelpCopy to ClipboardDownload CSV Answer: (69.14, 71.38) Question 10 The population standard deviation for the heights of dogs, in inches, in a city is 3.7 inches. If we want to be 95% confident that the sample mean is within 1 inch of the true population mean, what is the minimum sample size that can be taken? z0.101.282z0.051.645z0.0251.960z0.012.326z0.0052.576 Use the table above for the z-score, and be sure to round up to the nearest integer. Answer: 53 dog heights Question 11 Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) A random sample of house sizes in major city has a sample mean of x¯=1204.9 sq ft and sample standard deviation of s=124.6 sq ft. Use the Empirical Rule to determine the approximate percentage of house sizes that lie between 955.7and 1454.1 sq ft. Round your answer to the nearest whole number (percent). Answer: 95 % Question 12 The graph below shows the graphs of several normal distributions, labeled A, B, and C, on the same axis. Determine which normal distribution has the smallest standard deviation. A B C Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! We estimate that 95% of text messages have lengths between 23 and 47 characters. Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) • σ p ̂ = 0 .0 21 Question 17 The lengths of text messages are normally distributed with an unknown population mean. A random sample of text messages is taken and results in a 95% confidence interval of (23,47) characters. What is the correct interpretation of the 95% confidence interval? We estimate with 95% confidence that the true population mean is between 23 and 47 characters. We estimate with 95% confidence that the sample mean is between 23 and 47 characters. Question 18 Given the plot of normal distributions A and B below, which of the following statements is true? Select all correct answers. Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! The standard deviations of A and B are equal. Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) A normal bell curve labeled Upper A and a normal elongated curve labeled Upper B are centere at the same point. Normal curve Upper B is narrower and above normal curve Upper A. A has the larger mean. B has the larger mean. The means of A and B are equal. A has the larger standard deviation. B has the larger standard deviation. Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) That is correct! Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6) Question 19 A tour guide company is trying to decide if it is going to increase the cost of its tours to cover its sunk costs. They find that the average sunk cost per tour is $58, with a standard deviation of $18. If they take a random sample of 36 tours, identify each of the following to help them make their decision and round to the nearest hundredth if necessary: Answer: μ = 58 σ = 18 n = 36 μ x = 58 σ x = 3 Question 20 From a recent company survey, it is known that the proportion of employees older than 55 and considering retirement is 8%. For a random sample of size 110, what is standard deviation for the sampling distribution of the sample proportions, rounded to three decimal places? Answer: 0.26 Question 21 Math 225n Statistics exam Questions and Answers guaranteed Success. Chamberlain College of Nursing(week 6)