According to the American Automobile Association, the average cost of a gallon of regular unleaded fuel at gas stations in January 2019 was $3.5. Assume that the standard deviation of such costs was $4.75. Suppose that a random sample of 56 gas stations was selected from the population and the cost per gallon of regular unleaded fuel was determined for each gas station. Consider X¯bar, the sample mean cost per gallon. (a) Describe the sampling distribution of X¯bar. (b)Find the probability that the sample had a mean fuel cost between $3.8 and $4. (c) How would the sampling distribution of X¯bar change if the sample size were doubled?

Q: Assume that the scores of a college entry exam are normally distributed with a mean of 400 and a…

A: Given,mean(μ)=400standard deviation(σ)=60

Q: The length of human pregnancies from conception to birth varies according to a distribution that is…

A: Given that  Mean =266 Population standard deviation =16 Sample size n=6

Q: The number of ants in a group is normally distributed with a mean of 67.0 and a standard deviation…

A: Let X be the random variable for the number of ants in a group. Given that, X~N(μ=67.0, σ=83.64)…

Q: Total plasma volume is important in determining the required plasma component in blood replacement…

A: Solution

Q: According to one study, the average hours of sleep on a weeknight for men was 6.9 hours with a…

A:

Q: 2. The average time spent sleeping (in hours) for a group of medical residents at a hospital can be…

A: Given that  X~N(μ= 6.1 , σ= 1) μ= 6.1 , σ= 1 Formula for Z-score Z=(X-μ)/σ

Q: What hypothesis testing procedure should you use to answer these questions? 0.05 if it isn't Assume…

A:

Q: The weights of tablets are normally distributed with mean 254 mg and standard deviation 4 mg.  What…

A:

Q: Find the standard error of the distribution of sample proportions for samples of size 30 from a…

A: The objective of this question is to calculate the standard error (SE) of the distribution of sample…

Q: The mean gas mileage for a hybrid car is 57 miles per gallon. Suppose that the gasoline mileage is…

A:

Q: A prize winning crop of celery has an approximate normal distribution with a mean length of 15…

A:

Q: Total plasma volume is important in determining the required plasma component in blood replacement…

A: Sample size Sample mean Population standard deviation

Q: Among health care workers at a local hospital, the average number of vacation days taken per year is…

A: The mean is 5 and the standard deviation is 2.5.

Q: Assume that the average length of some wire is 52 inches with a standard deviation of 6.5 inches. At…

A: Given: The average length of the wire, μ=52 Standard deviation, σ=6.5 We need to determine at most…

Q: What proportion of skiers will finish the race in exactly one minute?

A: The tume it takes for downhill skiers to finish a race follows a Normal distribution with a mean of…

Q: A random sample of 100 male students is drawn from a particular class. The mean and standard…

A:

Q: The lengths of individual fish in a pond have a non-Normal distribution with a mean of 18.6 cm and a…

A:

Q: The age of customers for a particular retail store follows a normal distribution with a mean of 37.5…

A: Given Mean=37.5 Standard deviation=7.6

Q: In a recent awards ceremony the age of the winner for the best actor award was 34 and the age of the…

A:

Q: The cost of repairs for a fleet of motorcycles follows a normal distribution, with a monthly average…

A: Given Information: Mean value (u) = $ 1280  Standard deviation (s) = $ 420

Q: A fruit-canning company produces 250ml pineapple juice cans at its bottling plant. The population…

A: Given that, The population standard deviation for volume of pineapple juice filled in the cans is,…

Q: R can be used to find the critical value for an F distribution for a given significance level. For…

A: k=4 n=8

Q: For a random sample of 90 overweight men, the mean number of pounds that they were overweight was…

A:

Q: Assume the annual day care cost per child is normally distributed with a mean of ​$9000 and a…

A:

Q: Sketch the distribution of heights. What percentage of students are over 73.38 inches tall? What…

A: “Since you have asked multiple questions, we will solve the first question for you. If you want any…

Q: The age distribution of a sample of 5000 persons is bell shaped with a mean of 40 years and a…

A: GivenMean(μ)=40standard deviation(σ)=12

Q: The mean gas mileage for cars driven by the students at Chillville High Schoo is 28.0 miles per…

A: Normal distribution is continuous distribution which has many real life applications. Standard…

Q: Among health care workers at a local hospital, the average number of vacation days taken per year is…

A: Solution-: Given: μ=5,σ=2.5,n=50 We find the standard error for the sampling distribution =?

Q: Assume that adults have IQ scores that are normally distributed with a mean of 100.3 and a standard…

A: Assume that adults have IQ scores that are normally distributed with a mean of 100.3 and a standard…

Q: Suppose the durations of human pregnancies follow a mound-shaped distribution with a mean of 266…

A:

Q: The U.S. Department of Transportation provides the number of miles that residents of the 75 largest…

A: There are two independent populations. Those which are named as Buffalo residents and Boston…

Q: Use the empirical rule to estimate the number of farms whose land and building values per acre are…

A: here given , The mean value of land and buildings per acre from a sample of farms is ​$1600​,with a…

Q: Can the standard deviation of a data set be zero

A: Standard deviation can not be negative.

Q: The lengths of a large stock of titanium rods follow a normal distribution with a mean (u) of 440 mm…

A: Given that, The lengths of a large stock of titanium rods follow a normal distribution with a mean…

Q: Total plasma volume is important in determining the required plasma component in blood replacement…

A: The sample size is 44, sample mean is 37.5 and population standard deviation is 7.50.

Q: The published proportion of traffic fatalities attributed to motorcycle accidents is 0.14. A…

A:

Q: A taxicab company in New York City analyzed the daily number of miles driven by each of its drivers.…

A: It is given that the number of miles driven is normally distributed with mean 200 miles and standard…

Q: Cholesterol is a fatty substance that is an important part of the outer lining (membrane) of cells…

A:

Q: What is the SD of a distribution if the mean is 4.5 and a z score of 3.5 corresponds to a raw score…

A: GIVEN DATA, μ=4.5z score =3.5raw score =x=15standard deviation =σ=?

Q: Assume the average amount of caffeine consumed daily by adults is normally distributed with a mean…

A: The detailed solution is as follows below:

Q: To compare the dry braking distances from 30 to 0 miles per hour for two makes of automobiles, a…

A: Given,X1=42, σ1=4.7, n1=35X2=45, σ2=4.4 , n2=35and level of significance α=0.10

Estimation

A new framework of data analysis where the new statistical methods are used for interpreting the results and analyzing the data is known as estimation in statistics.