wants to stimate the standard deviation of the time takes a bus to travel between two steps in a chy . To develop an estimate for the standard deviation , the city has collected a random sample of the times required for 19 trips The sample standard deviation is 5.9minutes Based on these data what is the 90% conlidence interval estimate for the true population standard deviation les ses minutes Round to two decimal places as needed )
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The commute times for workers in a city are normally distributed with an unknown population mean and standard deviation. If a random sample of 37 workers is taken and results in a sample mean of 31 minutes and sample standard deviation of 5 minutes. Use Excel to find a 95% confidence interval estimate for the population mean using the Student's t-distribution. Round the final answers to two decimal places.
Becky Sharp is trying to create an estimate for the amount of time a carriage ride from Brighton to the city of London takes. She asks her friends and acquaintances to record the time spent traveling if they make the trip during the month of June. Out of the 85 trips, She finds a mean travel time of 660 minutes, with a standard deviation of 80 minutes. a. Are there any issues with creating a confidence interval if our population...
Suppose a random sample of 13 items produces a sample standard deviation of 16. a. Use the sample results to develop a 90% confidence interval estimate for the population variance. b. Use the sample results to develop a 95% confidence interval estimate for the population variance. (Round to two decimal places as needed.) b. so2s (Round to two decimal places as needed.)
Suppose that pizza delivery times are normally distributed with a population standard deviation of 6 minutes. A random sample of 50 pizza delivery restaurants is taken and has a sample mean delivery time of 36 minutes. Construct a 90% confidence interval for the population mean delivery time. What is the sample mean? 6 1.87 36 1.64 What is the sample size? 8.33 90 50 36 What is the population standard deviation? 0.85 50 36 6 What is the confidence level?...
Suppose a random sample of 23 items produces a sample standard deviation of 11. a. Use the sample results to develop a 90% confidence interval estimate for the population variance. b. Use the sample results to develop a 95% confidence interval estimate for the population variance. a. Iso²s (Round to two decimal places as needed.) b. sos (Round to two decimal places as needed.)
- publisher wants to estimate the mean length of time in minutes) all adults spend reading newspapers. To determine this estimate the publisher takes a random sample of 15 people and obtain the results below. From past studies, the bisher assumes als 1.9 minutes and that the population of times is normally distributed 10 12 10 7 10 11 6 7 6 Construct the 90% and 99% confidence intervals for the population mean. Which interval is wider convenient, use technology...
Bruce Tay, intern at Mark-Analytics, is conducting a study in which a population mean will be estimated using a 92% confidence interval. The estimate needs to be within 15 of the actual population mean. The population standard deviation is estimated to be around 60. The necessary sample size should be at least (round up!): answer .. The weights of aluminum castings produced by a process are normally distributed. A random sample of 6 castings is selected; the sample mean weight...
a)A sample of 30 patients in a doctor's office showed that they had to wait for an average of 33 minutes before they could see the doctor. The sample standard deviation is 14 minutes. Assume the population of waiting times is normally distributed.At 90% confidence, compute the lower bound of interval estimate for the average waiting time of all the patients who visit this doctor. b)A university planner wants to determine the proportion of spring semester students who will attend...
A sample of 16 elements is selected from a population with a reasonably symmetrical distribution. The sample mean is 100 and the sample standard deviation is 40. We can say that we are 90% confident that μis between what two numbers? 11. What is the lower number? Maintain three decimal points in your calculations and give at least two decimal points in your answer. 12. What is the upper number? Maintain three decimal points in your calculations and give at...
Suppose that the wait times for patients in an emergency room are normally distributed with an unknown mean and standard deviation. A random sample of 18 patients is taken and gives a sample mean of 25 minutes and a sample standard deviation of 2 minutes. As found above, the EBM, margin of error, for a 95% confidence interval estimate for the population mean using the Student's t-distribution is 0.99. Find a 95% confidence interval estimate for the population mean using...