Questions from Applied Statistics

Q: The city fuel economy of a 2009 Toyota 4Runner 2WD 6 cylinder

The city fuel economy of a 2009 Toyota 4Runner 2WD 6 cylinder 4 L automatic 5-speed using regular gas is a normally distributed random variable with a range 16 MPG to 21 MPG. (a) Estimate the standard...

Q: (a) Find the standard error of the mean for each

(a) Find the standard error of the mean for each sampling situation (assuming a normal population). (b) What happens to the standard error each time you quadruple the sample size? a. σ = 32, n = 4 b....

Q: What sample size would be needed to estimate the true proportion of

What sample size would be needed to estimate the true proportion of American households that own more than one DVD player, with 90 percent confidence and an error of ±0.02?

Q: What sample size would be needed to estimate the true proportion of

What sample size would be needed to estimate the true proportion of American adults who know their cholesterol level, using 95 percent confidence and an error of ±0.02?

Q: Inspection of a random sample of 19 aircraft showed that 15 needed

Inspection of a random sample of 19 aircraft showed that 15 needed repairs to fix a wiring problem that might compromise safety. How large a sample would be needed to estimate the true proportion of j...

Q: Find the 95 percent confidence interval for the population variance from these

Find the 95 percent confidence interval for the population variance from these samples. a. n = 15 commuters, s = 10 miles driven b. n = 18 students, s = 12 study hours

Q: The weights of 20 oranges (in ounces) are shown below

The weights of 20 oranges (in ounces) are shown below. Construct a 95 percent confidence interval for the population standard deviation. Note: Scale was only accurate to the nearest ¼ ou...

Q: At a certain Noodles & Company restaurant, customers arrive during the

At a certain Noodles & Company restaurant, customers arrive during the lunch hour at a rate of 2.8 per minute. What is the probability that (a) at least 30 seconds will pass before the net customer wa...

Q: A pediatrician’s records showed the mean height of a random sample of

A pediatrician’s records showed the mean height of a random sample of 25 girls at age 12 months to be 29.530 inches with a standard deviation of 1.0953 inches. Construct a 95 percent confidence interv...

Q: Find the 90 percent confidence interval for the standard deviation of gasoline

Find the 90 percent confidence interval for the standard deviation of gasoline mileage mpg for these 16 San Francisco commuters driving hybrid gas-electric vehicles.