It has been reported that the standard deviation of the speeds of drivers on Interstate 75...

It has been reported that the standard deviation of the speeds of drivers on Interstate 75 near Tifton, GA is 8 mph for all vehicles. A Department of Transportation engineer claims this is too low. A survey is conducted and for 30 drivers, the standard deviation is 10.5 mph. At  = 0.05 , is the engineer correct?

State:__________________________________ CV: use table E, F, G, CV=___________________ TV: z, t, or 2  (circle one), TV=________________ Decide:_________________________________ Summary: (remember to circle the correct description before completing the statement) There is/is not enough evidence to reject/support the claim that______________________ ________________________________________________________________________ _______________________________________________________________________

Expert Solution

There is enough evidence to reject/support the claim that standard deviation is as low as 8 mph.

orchestra answered 2 years ago

A variable of a population has a mean of muμ equals=75 and a standard deviation of...

A variable of a population has a mean of muμ equals=75 and a standard deviation of sigmaσ equals=18 a. Identify the sampling distribution of the sample mean for samples of size 36 b. In answering part (a), what assumptions did you make about the distribution of the variable? c. Can you answer part (a) if the sample size is 25 instead of 36? Why or why not? What is the mean of the sampling distribution?

A)The life expectancy in the United States has a mean of 75 with a standard deviation...

A)The life expectancy in the United States has a mean of 75 with a standard deviation of 7 years and follows a normal distribution. What is the probability of an individual living longer than 80 years? b)In the two upcoming basketball games, the probability that UTC will defeat Marshall is 0.63, and the probability that UTC will defeat Furman is 0.55. The probability that UTC will defeat both opponents is 0.3465. What is the probability that UTC will defeat Furman...

1. A test of reading ability has a population mean of 75 and a standard deviation...

1. A test of reading ability has a population mean of 75 and a standard deviation of 10 when given to third-graders. The distribution is known to be approximately normally distributed. a. What is the probability that a student will score above a 90? Show your calculation. b. What test score corresponds to the 25th percentile? Show your calculation. Say that you selected a random sample of 40 third-grade students from this population. c. What is the probability that the...

The mean of a population is 75 and the standard deviation is 13. The shape of...

The mean of a population is 75 and the standard deviation is 13. The shape of the population is unknown. Determine the probability of each of the following occurring from this population. a. A random sample of size 32 yielding a sample mean of 76 or more b. A random sample of size 160 yielding a sample mean of between 74 and 76 c. A random sample of size 218 yielding a sample mean of less than 75.2 (Round all...

The mean of a population is 75 and the standard deviation is 12. The shape of...

The mean of a population is 75 and the standard deviation is 12. The shape of the population is unknown. Determine the probability of each of the following occurring from this population. a. A random sample of size 35 yielding a sample mean of 78 or more b. A random sample of size 150 yielding a sample mean of between 73 and 76 c. A random sample of size 219 yielding a sample mean of less than 75.8

The average age for licensed drivers in a county is 42.6, with a standard deviation of...

The average age for licensed drivers in a county is 42.6, with a standard deviation of 12, and the distribution is approximately normal. A county police officer was interested in whether the average age of those receiving speeding tickets is less that the average age of the population who has a license. She obtained a sample of 16 drivers with speeding tickets. The average age for this sample was 34.4. Do all the steps of hypothesis testing using the 0.01...

Stock JAY has an expected return of 13 percent and a standard deviation of 75 percent....

Stock JAY has an expected return of 13 percent and a standard deviation of 75 percent. Stock ELIZABETH has an expected return of 9 percent and a standard deviation of 42 percent. The covariancr between the two stocks is .07. you invest 1/3 of your money in JAY and the rest in ELIZABETH. What is the variance of the portfolios returns?

A police officer is concerned about speeds on a certain section of Interstate 95. The data...

A police officer is concerned about speeds on a certain section of Interstate 95. The data accompanying this exercise show the speeds of 40 cars on a Saturday afternoon. Click here for the Excel Data File (HwySpeed 69 70 66 70 69 65 70 70 65 69 70 68 67 70 70 67 69 66 66 66 65 70 69 70 69 66 69 65 68 70 68 69 69 69 67 66 67 68 68 66 Click here for...

A traffic study conducted on an interstate highway shows that vehicle speeds (in mph) are normally...

A traffic study conducted on an interstate highway shows that vehicle speeds (in mph) are normally distributed with a mean of 61.3 and a standard deviation of 3.3. a) Sketch the distribution of vehicle speeds. Show 3 steps of standard deviation above and below the mean. b) If a vehicle is randomly checked, what is the probability that its speed is greater than 70? Include a sketch. c) If 5 vehicles are randomly sampled, what is the probability that their...

The speeds of car traveling on Interstate Highway I-35 are normally distributed with a mean of...

The speeds of car traveling on Interstate Highway I-35 are normally distributed with a mean of 74 miles per hour and a standard deviation of 6 miles per hour. (a) Find the percentage of the cars traveling on this highway with a speed i. of more than 85, ii. between 65 to 72. (b) If a BMW is at the speed that is faster than 90 percentage of cars, what is the speed of the BMW?

Question