A census of the labor force in a large metropolitan area found that the time it takes for people to commute to work has a mean of 20.5 minutes and a standard deviation of 15.4 minutes.what is the probability that a random sample of 40 people have a mean commute time that is greater than 25 minutes ?

A census of the labor force in a large metropolitan area found that the time it takes for people to commute to work has a mean of 20.5 minutes and a standard deviation of 15.4 minutes.what is the probability that a random sample of 40 people have a mean commute time that is greater than 25 minutes ?

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

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?
The term "Freshman 15" refers to the claim that college students typically gain 15 lb during their freshman year at college. Assume that the amounts of weight that male college students gain during their freshman year are normally distributed with a mean of 2.7 lb and a standard deviation of 11.4 lb. Find the probability that a randomly selected male college student gains 15 lb or more during his freshman year. What does the result suggest about the claim of the "Freshman 15"? ... The percentage of freshmen that gain 15 pounds or more in their first year of university is %. (Round to one decimal place as needed.)
The time that college students spend studying per week have a distribution that skewed to the right with a mean of 8.4 hours and a standard deviation of 2.7 hours. Find the probability that the mean time spent studying per week for a random sample of 40 is less than 7.5 hours.
According to College Board, the average out-of-state tuition for a four-year public college was $8,893 for the 2013-2014 academic year. There are a total of 629 four-year public institutions in the U.S. Assume that the standard deviation for the tuition for these colleges is $950. A random sample of 60 four-year public colleges was selected. What is the probability that the average tuition from this sample is less than $9,000?
A market researcher analyzes how many cases of bottled water a customer buys at a grocery store. The distribution has a mean of 3.0 and standard deviation of 0.7. Assuming a random sample of 400 customers, what is the probability that the total cases of bottled water purchased is less than 1,186?
A courier services company has found that the delivery time for packages is normally distributed, with a mean of 14 hours and a standard deviation of 2 hours. What is the probability that a randomly selected package will be delivered in between 12 and 15 hours?
Last year, a person wrote 118 checks. Let the random variable x represent the number of checks he wrote in one day, and assume that it has a Poisson distribution. What is the mean number of checks written per day? What is the standard deviation? What is the variance?
A manufacturing process produces potato chip bags that have Normally distributed weights, with a mean weight of 15 oz. and a standard deviation of .3 oz. What is the probability that 16 randomly selected bags have a mean weight that exceeds 15.2 oz?
An ACNielsen study indicates that mobile subscribers between 18 and 24 years of age spend a substantial amount of time watching video on their devices, reporting a mean of 325 minutes per month. Assume that the amount of time spent watching video on a mobile device per month isnormally distributed and that the standard deviation is 50 minutes. a. What is the probability that an 18- to 24-year-old mobile subscriber spends less than 300 minutes watching video on his or her mobile device in a given month? b. What is the probability that, for 2 randomly selected 18- to 24-year-old mobile subscribers, both spent less than 300 minutes watching video on their mobile device in a given month? c. What is the probability that, for 2 randomly selected 18- to 24-year-old mobile subscribers, the sum of time they spent watching video on their mobile device in a given month is less than 600 minutes? d. What is the number of minutes such that 25% of all 18- to 24-year-old mobile subscribers will spend…
A report stated that after obtaining a bachelor's degree, 43% of college students enroll in a graduate degree program. For a random sample of 61 undergraduate students, find the mean, variance and standard deviation for the number of students who will enroll in a graduate degree program after obtaining a bachelor's degree. a.) mean b.) variance c.) standard deviation (round to two decimal places)
Assume that cans of Coke are filled so that the actual amounts have a mean of 12.00 oz and a standard deviation of 0.11 oz. However, 36 random cans of coke were selected and found to have a mean of 12.19 oz. Find the probability that a single can of Coke has at least 12.19 oz.
A report on egg consumption shows that people living in China eat an average of 196 eggs each year with a standard deviation of 18.3 eggs. If a group of 81 Chinese people are selected at random, what is the probability that the average egg consumption of this group will be more than 200 eggs?