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Unformatted text preview: Assignment 19 Directions: Find the critical / 2 Z value given the following confidence levels. 1. 98% 2. 99% 3. 95% 4. 90% 5. 92% 6. 96% 7. 94% 8. 97% Assignment 20 9. A 99% confidence interval was constructed to estimate the mean and it the resulting interval is [9.68, 11.02]. Write a statement to correctly interpret the interval. 10. Interpret the confidence coefficient used in problem 9. In other words, what does it mean to say we are 99% confident? 11. If an estimator is unbiased, what does that mean in plain terms? For problems 12 15, calculate the Margin of Error that would be used when estimating the mean for the following scenarios: 12. The confidence level is 99%. The sample size is 37. The sample mean is 25, and the population standard deviation is 4. 13. The confidence level is 92%. The sample size is 49. The sample mean is 512, and the population standard deviation is 28. 14. The confidence level is 90%. The sample size is 100. The sample mean is 69, and the population standard deviation is 3.2. 15. The confidence level is 94%. The sample size is 32. The sample mean is 100, and the population standard deviation is 14.6. For problems 16 19, use the provided information to construct a confidence interval to estimate the population mean. 16. Salaries of college statistics professors at Florida public universities: Confidence level = 95%, n =36, x =$85,113, and =$11,024. 17. Speeds of drivers ticketed in a 65mph zone: Confidence level = 98%, n =31, x =81, and =3.4. 18. Credit scores: Confidence level = 91%, n =48, x =688, and =67. 19. Losses of patrons at the Seminole Casinos: Confidence level = 93%, n =50, x =170, and =89. For problems 20 23, use the information provided to determine the sample size needed to construct a confidence interval to estimate the population mean. 20. Margin of error: 0.19 Confidence level: 95% Population standard deviation: 4 21. Margin of error: 15 Confidence level: 90% Population standard deviation: 102 22. Margin of error: 0.68 Confidence level: 98% Population standard deviation: 3.9 23. Margin of error: 1 Confidence level: 99% Population standard deviation: 2.8 The following Minitab display was created from speed data collected on a strip of I95 where the speed limit is posted as 55mph. Use the Minitab display below to answer questions 24 and 25: 24. Identify the point estimate for the population mean. 25. Interpret the 95% confidence interval provided by Minitab. Putting it all together 26. A survey of thirtyone, 2005 Major League Baseball salaries for pitchers playing in the National League had a mean of $2,522,785 and a standard deviation of $4,065,579. Construct the 98% confidence interval for the true average salary for all NLMLB pitchers in 2005....
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This note was uploaded on 01/11/2012 for the course STA 2122 taught by Professor Staff during the Winter '08 term at FIU.
 Winter '08
 STAFF

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