This quiz works best with JavaScript enabled. Home > Ugc Net > Paper 1 > Research Stats > Confidence Intervals – Quiz 3 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Confidence Intervals Quiz 3 (30 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. Use the z table or your calculator to find the critical value (Z*) that corresponds to 92% confidence. A) 1.75. B) 1.96. C) 1.81. D) 1.41. Show Answer Correct Answer: A) 1.75. 2. Find the t* value for a 99% confidence interval with a sample of 23 people. A) 1.714. B) 1.711. C) 2.064. D) None of these. Show Answer Correct Answer: D) None of these. 3. What is the alpha value for a 95% confidence level? A) .05. B) 1.05. C) 1. D) 5. Show Answer Correct Answer: A) .05. 4. In a survey of 250 Internet users, 195 have high-speed Internet access at home. Find a point estimate for the proportion of all Internet users who have high-speed Internet access at home. A) 0.22. B) 0.78. C) 195. D) 1.28. Show Answer Correct Answer: B) 0.78. 5. A nurse at a local hospital is interested in estimating the birth weight of infants. How large a sample must sheselect if she desires to be 99% confident that the true mean is within 4 ounces of the sample mean? Thestandard deviation of the birth weights is known to be 9 ounces. A) 30. B) 7. C) 34. D) 15. Show Answer Correct Answer: C) 34. 6. Construct a 95% confidence interval:A random sample of 75 oak trees has a mean height of 62 ft. Assume a population standard deviation of 3.8 ft. A) (60.87, 63.13). B) (61.14, 62.86). C) (58.20, 65.80). D) (60.28, 63.72). Show Answer Correct Answer: B) (61.14, 62.86). 7. Construct a 90% confidence interval of a random sample size of 19 cows with a mean of 155.526 and a standard deviation of 19.993. A) (147.57, 163.48). B) (147.59, 163.46). C) (143.69, 167.36). D) (146.54, 164.52). Show Answer Correct Answer: A) (147.57, 163.48). 8. Given the Critical Value of Z = 2.11, find the Confidence Level. A) 98.26%. B) 99%. C) 96.52%. D) 95%. Show Answer Correct Answer: C) 96.52%. 9. What is the t value associated with 90% confidence and a sample size of 15? A) 1.341. B) 1.753. C) 1.761. D) 1.345. Show Answer Correct Answer: C) 1.761. 10. Most people can roll their tongues, but many can't. The ability to roll the tongue is genetically determined. Suppose we are interested in determining what proportion of students can roll their tongues. We test a simple random sample of 400 students and find that 317 can roll their tongues. The margin of error for a 95% confidence interval for the true proportion of tongue rollers among students is closest to A) 0.0008. B) 0.02. C) 0.04. D) 0.003. Show Answer Correct Answer: C) 0.04. 11. The amount added and subtracted to the statistic. A) Population. B) Z Score. C) Confidence Interval. D) Margin of Error. Show Answer Correct Answer: D) Margin of Error. 12. The football coach randomly selected ten players and timed how long each player took to perform a certain drill. The times (in minutes) were:13.2, 5.1, 7.5, 8.0, 12.7, 7.6, 13.8, 14.5, 7.7, and 10.5. Determine a 95 percent confidence interval for the mean time for all players. A) (7.72, 12.40). B) (2.40, 7.72). C) (2.30, 7.82). D) (7.82, 12.30). Show Answer Correct Answer: A) (7.72, 12.40). 13. Mr. Kellar's class would like to estimate the mean number of times females interact with Instagram at Northland. Find a 95% confidence interval based on the data students gathered:10, 15, 20, 8, 7, 5, 15, 20, 7, 8, 9, 6 A) (7.5, 14.2). B) (7.7, 14.9). C) (7.8, 15). D) (7.6, 14.1). Show Answer Correct Answer: A) (7.5, 14.2). 14. Determine the sampling error if the grade point averages for 10 randomly selected students from a class of 125students has a mean of x = 2.3. Assume the grade point average of the 125 students has a mean of $\mu$ = 2.7. A) 2.1. B) 0.04. C) -0.4. D) 2.5. Show Answer Correct Answer: C) -0.4. 15. The ..... is the maximum likely difference between the point estimate of a parameter and the actual value of the parameter. A) Inference. B) Confidence Level. C) Point Estimate. D) Maximum Error of Estimate. Show Answer Correct Answer: D) Maximum Error of Estimate. 16. Find the minimum sample size needed to be 4% within the true proportion if you are 95% confident and p-hat = 0.6 A) 12. B) 6. C) 577. D) 961. Show Answer Correct Answer: C) 577. 17. It was found that in a sample of 90 teenage boys, 70% of them have received speeding tickets. What is the 90% confidence interval of the true proportion of teenage boys who have received speeding tickets? A) (0.621, 0.780). B) (0.584, 0.830). C) (0.591, 0.812). D) (0.615, 0.805). Show Answer Correct Answer: A) (0.621, 0.780). 18. A laboratory tested 72 candy bars found in vending machines and found that the mean number of calories was 240 with s = 19.6 calories. Construct a 95% confidence interval for the mean calories of all candy bars found in vending machines. A) (234.04, 245.96). B) (235.40, 244.60). C) (236.21, 243.79). D) (235.47, 244.53). Show Answer Correct Answer: B) (235.40, 244.60). 19. If the population standard deviation is unknown which distribution should be used to find a confidence interval for a mean? A) Chi-square distribution. B) Binomial distribution. C) T-distribution. D) Normal distribution. Show Answer Correct Answer: C) T-distribution. 20. In a survey of 104 students, it was found that 79 went to the homecoming game this year. Find p-hat first and use z formula with p-hat in it.Calculate a 99% confidence interval for p. A) (0.691, 0.829). B) (0.652, 0.868). C) (0.678, 0.842). D) (0.685, 0.895). Show Answer Correct Answer: B) (0.652, 0.868). 21. Find the critical value Zc that corresponds to a 98% confidence level A) 1.645. B) 1.96. C) 2.33. D) 2.575. Show Answer Correct Answer: C) 2.33. 22. A research company wants to estimate the proportion of people who like oatmeal. They want the confidence level to be 95%. The company gets 325 people to sign up for the survey, but on the day that the survey is issued, only 250 people show up and take the survey. What happens to the confidence interval? A) It gets larger. B) It gets smaller. C) It stays the same. D) Too little information given. Show Answer Correct Answer: A) It gets larger. 23. A random sample of 15 DVD players has a mean price of $ 64.30 and a standard deviation of $ 5.60. Find a 95% confidence interval for the mean price of all DVD players. A) (61.47, 67.13). B) (61.10, 67.51). C) (61.22, 67.38). D) (61.20, 67.40). Show Answer Correct Answer: D) (61.20, 67.40). 24. Choose the appropriate type of confidence interval for the situation described below.A random sample of 9 refrigerators has a mean cost of $ 1263 and a standard deviation of $ 530.75. Construct a 90% confidence interval for the average cost of a refrigerator. A) Z-distribution for proportions. B) T-distribution for proportions. C) T distribution for mean cost. D) Z-distribution for mean cost. Show Answer Correct Answer: C) T distribution for mean cost. 25. In a recent study of 42 eighth graders, the mean number of hours per week that they watched television was19.6. Assume the population standard deviation is 5.8 hours. Find the 98% confidence interval for thepopulation mean. A) (17.5, 21.7). B) (14.1, 23.2). C) (19.1, 20.4). D) (18.3, 20.9). Show Answer Correct Answer: A) (17.5, 21.7). 26. Find the Critical Value for an 86% Confidence Level. A) 1.282. B) -1.47. C) 1.48. D) -1.48. Show Answer Correct Answer: C) 1.48. 27. A nutritionist found that in a sample of 80 families, 22% said they are apples at least once a week. Construct the 90% CI for the population proportion. A) (0.129, 0.311). B) (0.190, 0.250). C) (0.144, 0.296). D) (0.704, 0.856). Show Answer Correct Answer: C) (0.144, 0.296). 28. The standard IQ test has a mean of 97 and a standard deviation of 17. We want to be 95% certain that we arewithin 5 IQ points of the true mean. Determine the required sample size. A) 10. B) 72. C) 154. D) 45. Show Answer Correct Answer: D) 45. 29. A researcher studying reaction time of drivers states that, "A 95% confidence interval for the mean time it takes for a driver to apply the brakes after seeing the brake lights on a vehicle in front of him is 1.2 to 1.8 seconds. What are the point estimate and margin of error for this interval? A) Point estimate = 1.5 seconds; margin of error = 0.6 seconds. B) Point estimate = 1.5 seconds; margin of error = 0.3 seconds. C) Point estimate = 1.2 seconds; margin of error = 0.6 seconds. D) Point estimate = 1.2 seconds; margin of error = 0.3 seconds. Show Answer Correct Answer: B) Point estimate = 1.5 seconds; margin of error = 0.3 seconds. 30. Find the critical value tc necessary to form a 95% confidence interval with a sample size of 15. A) 1.960. B) 2.145. C) 2.131. D) 2.120. Show Answer Correct Answer: B) 2.145. ← PreviousNext →Related QuizzesPaper 1 QuizzesUgc Net QuizzesConfidence Intervals Quiz 1Confidence Intervals Quiz 2Confidence Intervals Quiz 4Analysis Of Variance QuizChi Square QuizCoefficient Of Variation Discrete Serious And Continuous Serious QuizConcept Of Point And Interval Estimation QuizConcept Of Sampling And Other Concepts Related To Sampling Quiz 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books