Question

A random sample of 10 drivers reported the below average mileage in the city for their cars.

18, 21, 24, 25, 25, 25, 25, 26, 29, & 31

The mean of the sample is 24.9 miles per gallon, with an associated standard deviation of about 3.6.

Find the 95% confidence interval for the average mileage of the cars for all of the drivers in the class. Assume all normality conditions apply.

Determine the approximate sample size needed to estimate the mean of the population with 90% confidence, if the desired margin of error for that estimate is 15. The population standard deviation is 100.

Answer #1

A random sample of ten 2011 sports cars is taken and their city
mileage is recorded. The results are as follows: 20 21 25 21 21 23
31 32 28 26 Assuming the population distribution is normal, compute
E, the margin of error for the t interval, for a 90% confidence
interval for m, the population mean of the city mpg for 2011 sports
cars. Question 7 options: a.) 2.531 b.) 3.546 c.) 1.843 d.)
4.128

One gallon of gas is put into each of 30 test cars. The
resulting gas-mileage values of the sample are computed with mean
of 28.5 gallons per mile, and standard deviation of 1.2 miles per
gallon. What is the 95% confidence interval estimate of the mean
mileage?

Suppose a newly released car has the average mileage of 26 mpg
and a standard deviation of 7. The mileage of these cars
approximately follow normal distribution. Consider a sample of size
of 15 cars
a.What is the probability that the sample mean is between 22 and
32?
b.If a sample of 16 cars are considered, what is the probability
that the mean mileage is
less than 27.5?
c. If a sample of 25 cars are considered, what is the...

An automobile manufacturer introduces a new model that
averages 27 miles per gallon in the city. A person who plans to
purchase one of these new cars wrote the manufacturer for the
details of the tests, and found out that the standard deviation is
3 miles per gallon. Assume that in-city mileage is approximately
normally distributed (use z score table)
a) What percentage of the time is the car averaging less than
20 miles per gallon for in-city driving.
b)...

We expect a car's highway gas mileage to be related to its city
gas mileage (in miles per gallon, mpg). Data for all 1137 vehicles
in the government's 2013 Fuel Economy Guide give the
regression line
highway mpg = 6.785 + (1.033 × city mpg)
for predicting highway mileage from city mileage.
(a) What is the slope of this line? (Enter your answer to three
decimal places.)
____mpg
Say in words what the numerical value of the slope tells us....

A random sample of 16 mid-sized cars, which were tested for fuel
consumption, gave a mean of 26.4 miles per gallon with a standard
deviation of 2.3 miles per gallon. Assuming that the miles per
gallon given by all mid-sized cars have a normal distribution, find
a 90% confidence interval for the population mean.

Gas mileage, in miles per gallon, was measured for five 2012
Ford Explorer SUVs. The five results are as follows: 20.4 19.6 17.1
17.9. 18.7
a. Compute the sample mean.
b. Compute the sample variance and standard deviation.
c. Construct a 95% confidence interval for the average gas
mileage in miles per gallon.

Question 1:
Almost all employees working for financial companies in New York
City receive large bonuses at the end of the year. A sample of 63
employees selected from financial companies in New York City showed
that they received an average bonus of $ 61 , 000 last year with a
standard deviation of $ 16 , 000 . Construct a 98 % confidence
interval for the average bonus that all employees working for
financial companies in New York City...

A car salesperson claims that the mean gas mileage for its
luxury sedan is at least 25 miles per gallon (mpg). A random
sample of 30 cars has a mean gas mileage of 24 mpg and a (sample)
standard deviation of 3.5 mpg.
a) State the null and alternative
hypotheses.
b) Determine the P-Value
c) State the outcome of the test at α =
0.05

oints) A random sample of 45 mid-sized cars tested for fuel
consump- tion gave a mean of 28.6 miles per gallon with a sample
standard deviation of 2.5 miles per gallon. Find a 98% confidence
interval for the population

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 11 minutes ago

asked 14 minutes ago

asked 29 minutes ago

asked 38 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago