The department of transportation is interested in estimating the average speed of drivers at a certain point on Washington Center Road. After random sampling 50 cars they find the sample average to be 49.6 mph with a standard deviation of 6.7 mph. Calculate a 95% confidence interval for the average speed of all drivers at that point on Washington Center Road.
The department of transportation is interested in estimating the average speed of drivers at a certain...
90) The Department of Transportation would like to test the hypothesis that the average age of cars on the road is less than 12 years. A random sample of 45 cars had an average age of 10.6 years. It is believed that the population standard deviation for the age of cars is 4.1 years. The Department of Transportation would like to set a = 0.05.
A 95% confidence interval for the average speed of drivers on the New York State Thruway is: (65 mph, 75 mph). What is the value of the point estimate? a. 65 mph b. 5 mph c. 10 mph d. 70 mph
A meteorologist in Jenkins county is interested in estimating the average annual rainfall of the region. The annual rainfall is assumed to follow a normal distribution. She takes a sample of last 10 years and obtains an alterage annual rainfall of 39.5 inches and a standard deviation of 3.8 inches. Estimate a 95% confidence interval for the population mean. 39.5 +/-
The Highway Safety Department wants to study the driving habits of individuals. A sample of 81 cars traveling on the highway revealed an average speed of 67 miles per hour with a standard deviation of 9 miles per hour. The confidence interval found out to be 64.36 to 69.64. What is the correct interpretation of the 95% CI? A. The highway speed is between 64.36 to 69.64 mph 95% of the time. B. We are 95% confident that speed on...
A shoe company is interested in estimating the average amount customers spent at their new store in a mall. A sample of 25 customers produced a mean spending of RM150 and with standard deviation of RM20. A 95% confidence interval for the true mean is: A. RM150 ± 164.80 C. RM150 ± 8.26 B. RM150 ± 8.24 D. RM150 ± 165.12
Question 2 (15 marks) Police departments often try to control traffic speed by placing speed-measuring machines on roads that tell motorists how fast they are driving. Traffic safety experts must determine where machines should be placed. In one recent test, police recorded the average speed clocked by cars driving on one busy street close to an elementary school. For a sample of 16 speeds, it was determined that the average amount over the speed limit for the 16 clocked speed...
(3 points) The Highway Safety Department wants to study the driving habits of individuals. A sample of 28 cars traveling on a particular stretch of highway revealed an average speed of 69.9 miles per hour with a standard deviation of 4.2 miles per hour. Round to 4 decimal places. 1.Calculate a 95% confidence interval for the true mean speed of all cars on this particular stretch of highway. ( , ) 2. What sample size is needed to estimate the...
You are interested in estimating the proportion of students at OSU who plan to study abroad. You construct a 95% confidence interval based on a survey of a random sample of 125 students, and the interval ends up being from 0.109 to 0.243. If you had instead constructed a 99% confidence interval based on the same sample of data, rather than a 95% confidence interval, how would the center of the interval change? A More information is needed in order...
(3 points) The Highway Safety Department wants to study the driving habits of individuals. A sample of 30 cars traveling on a particular stretch of highway revealed an average speed of 66.1 miles per hour with a standard deviation of 8.5 miles per hour. Round to 4 decimal places. 1.Calculate a 95% confidence interval for the true mean speed of all cars on this particular stretch of highway. 2. What sample size is needed to estimate the true average speed...
A community health association is interested in estimating the average number of maternity days women stay in the local hospital. A random sample is taken of 16 women who had babies in the hospital during the past year. The following numbers of maternity days each woman was in the hospital are rounded to the nearest day. 1 7 5 Use these data and a population standard deviation of 1.25 to construct a 98% confidence interval to estimate the average maternity...