MATH 225N Week 6 Statistics Quiz Questions & Answers. (Latest 2020)

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Question 1 1/1 points 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 wa... s 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. ________________________________________ That is correct! ________________________________________ open paren 67 comma 87 close paren$$ open paren 67 comma 87 close paren - correct Answer Explanation Correct answers: • open paren 67 comma 87 close paren $\left(67,\ 87\right)$ • A confidence interval is an interval of values, centered on a point estimate, of the form (pointestimate−marginof error,pointestimate+marginof error) Using the given point estimate for the mean, x¯=77 and margin of error 10, the confidence interval is: (77−10,77+10)(67,87) • • • • Question 2 · 1/1 points A random sample of adults were asked whether they prefer reading an e-book over a printed book. The survey resulted in a sample proportion of p′=0.14, with a sampling standard deviation of σp′=0.02, who preferred reading an e-book. Use the empirical rule to construct a 95% confidence interval for the true proportion of adults who prefer e-books. ________________________________________ That is correct! ________________________________________ open paren 0 point 1 0 comma 0 point 1 8 close paren$$ open paren 0 point 1 0 comma 0 point 1 8 close paren - correct Answer Explanation Correct answers: • open paren 0 point 1 0 comma 0 point 1 8 close paren $\left(0.10,\ 0.18\right)$ • By the Empirical Rule, a 95% confidence interval corresponds to a z-score of z=2. Substituting the given values p′=0.14 and σp′=0.02, a confidence interval is (p′−z⋅σp′,p′+z⋅σp′)(0.14−2⋅0.02,0.14+2⋅0.02)(0.14−0.04,0.14+0.04)(0.10,0.18) • • • • Question 3 · 1/1 points 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? ________________________________________ That is correct! ________________________________________ 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. [Show More]

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