The average fuel efficiency of U.S. light vehicles (cars, SUVs, minivans, vans, and light trucks) for 2005 was 21 miles per gallon (mpg). If the standard deviation of the population was 2.8 and the gas ratings were normally distributed, (a) what is the probability that the fuel used for a random sample of 25 light vehicles is under 18? (b) between 20 and 24?

The average fuel efficiency of U.S. light vehicles (cars, SUVs, minivans, vans, and light trucks) for 2005 was 21 miles per gallon (mpg). If the standard deviation of the population was 2.8 and the gas ratings were normally distributed, (a) what is the probability that the fuel used for a random sample of 25 light vehicles is under 18? (b) between 20 and 24?

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

See similar textbooks

Similar questions

The average smartphone user used 606 megabytes of data per month. Assume the standard deviation of data usage was 240 megabytes per month. A random sample of 60 smartphone users was selected. a. What is the expected value of the sample mean? b. What is the standard deviation of the sample mean? c. What is the probability that the averaged amount of data used in this sample was between 540 and 580?
Suppose that the miles-per-gallon rating of passenger cars is a normally distributed random variable with a mean and a standard deviation of 38.8 mpg and 4.1 mpg, respectively. What is the probability that a randomly selected passenger car gets at least 45 mpg? What is the probability that a randomly selected passenger car gets between 35 and 40 mpg? An automobile manufacturer wants to build a new passenger car with an mpg rating that improves upon 99% of existing cars. What is the minimum mpg that would achieve this goal?
A new species of dragonfly has an approximate body length of 45 mm with a standard deviation of 3 mm. In a sample of 40 dragonflies, what is the probability that the sample mean of the body length of the sample is between 44.5 and 45.5?
The daily sales of a small retail store in tokyo for the last 365 days are normally distributed with a mean of $2050, and a standard deviation of $300. From a sample of 49 days, what is the probability of having a sample mean less than $2000?
The weights of Australian Cattle Dogs are normally distributed with a mean of 25 kg and a standard deviation of 4 kg. What is the probability (%) that a randomly selected dog weighs between 23 kg and 32 kg?
The average fuel efficiency of U.S. light vehicles (cars, SUVs, minivans, vans, and light trucks) for 2005 was 21 miles per gallon (mpg). If the standard deviation of the population was 2.8 and the gas ratings were normally distributed, (a) what is the probability that the mean mpg for a random sample of 25 light vehicles is under 18? (b) between 20 and 24?
The producer of a weight-loss pill advertises that people who use the pill lose, after one week, an average (mean) of 1.75 pounds with a standard deviation of 1.02 pounds. In a recent study, a group of 60 people who used this pill were interviewed. The study revealed that these people lost a mean of 1.9 pounds after one week. If the producer's claim is correct, what is the probability that the mean weight loss after one week on this pill for a random sample of 60 individuals will be 1.9 pounds or less? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.
For the midterm exam in science of grade 8 students, the mean grade is 82 with standard deviation of 13. A random sample of size 30 will be taken. a. What is the probability that the sample mean is less than 75? b. What is the probability that the sample mean is greater than 90?
If the mean and standard deviation of cell sap values for healthy plants are 120 and 15 micrograms per 100 ml, respectively, what is the probability that a random sample of 50 normal plants will yield a mean between 115 and 125 micrograms per 100 ml?
A new car that is a gas- and electric-powered hybrid has recently hit the market. The distance travelled on 1 gallon of fuel is normally distributed with a mean of 55 miles and a standard deviation of 8 miles. Find the probability of the following events: The car travels between 49 and 63 miles per gallon. Probability =
Suppose a researcher pbserves a population of 12 people and computes SS=204. What is the variance? What is the standard deviation?