Police recorded the average speed of cars driving on a busy street by a school. For a sample of 16 speeds, it was determined that the average amount over the speed limit for the 16 speeds was 11.4 mph with a standard deviation of 6 mph. The 90% confidence interval estimate for this sample is 8.77 mph to 14.03 mph. a) What is the margin of error for this problem? b) What size sample is needed to reduce the margin of error to no more than 1 17

Police recorded the average speed of cars driving on a busy street by a school. For a sample of 16 speeds, it was determined that the average amount over the speed limit for the 16 speeds was 11.4 mph with a standard deviation of 6 mph. The 90% confidence interval estimate for this sample is 8.77 mph to 14.03 mph. a) What is the margin of error for this problem? b) What size sample is needed to reduce the margin of error to no more than 1 17

ENGR.ECONOMIC ANALYSIS

14th Edition

ISBN:9780190931919

Author:NEWNAN

Publisher:NEWNAN

Chapter1: Making Economics Decisions

Section: Chapter Questions

Problem 1QTC

See similar textbooks

Similar questions

If the level of confidence is lowered from 95% to 90 % , but the allowable error and the standard deviation remain the same, what happens to the required sample size?
A survey conducted by the American automobile association show that a family of four spent an average of $215.60 per day while on vacation. It's supposed to sample of 64 families of four vacationing at Niagara Falls resulted in a sample mean of $256.45 per day and a sample standard deviation of $76.50
A sample of 27 elements from a normally distributed population is selected. The sample mean is 14 with a sample standard deviation of 5. The 95% confidence interval for u is._____ a. 12.022 to 15.978 b. 9:000 to 19.000 c. 13.791 to 14.209 d. 15.886 to 12.114
Goofy Marketing Solutions conducted a survey among 16 randomly selected visitors to the newly opened Outlet Shoppes at Atlanta to measure their satisfaction with the shopping experience. The sample satisfaction score is normally distributed around a mean of �¯=67with a sample standard deviation of s=7.509. Determine the 95% confidence interval for the population mean from the sample. The upper limit of the 95% confidence interval is (rounded)....
A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 1010 nursing students from Group 1 resulted in a mean score of 55.755.7 with a standard deviation of 7.97.9. A random sample of 1515 nursing students from Group 2 resulted in a mean score of 65.665.6 with a standard deviation of 6.16.1. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ1�1 represent the mean score for Group 1 and μ2�2 represent the mean score for Group 2. Use a significance level of α=0.05�=0.05 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 2 of 4:…
A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 1010 nursing students from Group 1 resulted in a mean score of 55.755.7 with a standard deviation of 7.97.9. A random sample of 1515 nursing students from Group 2 resulted in a mean score of 65.665.6 with a standard deviation of 6.16.1. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ1�1 represent the mean score for Group 1 and μ2�2 represent the mean score for Group 2. Use a significance level of α=0.05�=0.05 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 3 of 4:…
High-power experimental engines are being developed by the Stevens Motor Company for use in its new sports coupe. The engineers have calculated the maximum horsepower for the engine to be 600HP600⁢HP. Nine engines are randomly selected for horsepower testing. The sample has an average maximum HP of 610610 with a standard deviation of 50HP50⁢HP. Assume the population is normally distributed. Step 1 of 2 : Calculate a confidence interval for the average maximum HP for the experimental engine. Use a significance level of α=0.05�=0.05. Round your answers to two decimal places.
A major newspaper (that rhymes with Small Street Journal) reported an average household income for its subscribers is $119,155. Assume this estimate of the mean household income is based on a sample of 80 subscribers, and, based on past studies, the population standard deviation is known to be sigma=$30,000. Construct a 95% confidence interval for the population mean. Group of answer choices $60,356 - $177,954 $118,420 - $119,890 $112,447 - $125,863 $112,581 - $125,729
A chemist measures the haptoglobin concentrations (in grams per liter) in the blood of eight healthy adults. The mean and standard deviation of the haptoglobin concentrations (in grams per liter) are 1.615 and 1.387 respectively. Obtain a 90% confidence interval for the mean haptoglobin concentration in adults.
According to R.L. Polk & Co., Americans held onto their new vehicles for an average of 71.4 months. A random sample of 60 adults who recently sold their new vehicle was selected. Assuming the standard deviation for this population is 15.8 months, the standard error for this sample is
A sample of 81 observations is taken from a normal population with a standard deviation of 6.The sample mean is 41. Determine the 99% confidence interval for the population mean.
The Ford Motor Company wishes to estimate the mean dollar amount of damage done to a Ford Explorer as a result of a 10 mph crash into the rear bumper of a parked car. The sample results are as follows.Sample Size = 36Sample Mean = $638 Sample Standard Deviation = $115 a. Construct a 95% confidence interval for the average dollar amount of damage.b. Interpret this interval.c. How large a sample size will need to be selected if we wish to have a 95% confidence interval for the average dollar amount of damage with a margin for error of $10?