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Statistical Analysis and Confidence Interval Estimations

An assignment covering statistical analysis and confidence interval estimations, focusing on real-world data interpretation.

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    Statistical Analysis and Confidence Interval Estimations Question 1 of 20 1.0 Points A lawyer researched the average number of years served by 45 different justices on the Supreme Court. The average number of years served was 13.8 years with a standard deviation of 7.3 years. What is the 95% confidence interval estimate for the average number of years served by all Supreme Court justices? Place your limits, rounded to 1 decimal place, in the blanks. Place you lower limit in the first blank. Place your upper limit in the second blank. When entering your answer do not use any labels or symbols. Simply provide the numerical value. For example, 12.3 would be a legitimate entry. Answer: 11.0 16.6 Question 2 of 20 1.0 Points If a sample has 25 observations and a 99% confidence estimate for is needed, the appropriate value of the t - multiple required is . Place your answer, rounded to 3 decimal places, in the blank. For example, 3.456 would be an appropriate entry. Answer: 2.787 Question 3 of 20 1.0 Points You are trying to estimate the average amount a family spends on food during a year. In the past, the standard deviation of the amount a family has spent on food during a year has been $1200. If you want to be 99% sure that you have estimated average family food expenditures within $60, how many families do you need to survey? Place your answer, a whole number, in the blank . For example, 1234 would be a legitimate entry. Answer: 417 Question 4 of 20 1.0 Points Senior management of a consulting services firm is concerned about a growing decline in the firm’s weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work - related activities in a typical week. Rather than reviewing the records of all the firm’s full - time employees, the management randoml y selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively. Construct a 99% confidence interval for the standard deviation of the number of hours this firm’s employees spend on work - related activities in a typical week. Place your LOWER limit, in hours, rounded to 1 decimal place, in the first blank. For example, 6.7 would be a legitimate entry. Place your UPPER limit, in hours, rounded to 1 decimal place, in the second blank. For example, 12.3 would be a legitimate entry. Answer:5.9, 9.5

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