Question

Assume that fuel economy follows a normal distribution with mean of 24 mpg (miles per gallon) and a standard deviation of 6 mpg.

(a) In what interval would you expect the central 68% of autos to be found?

(b) What percent of autos should get more than 30 mpg?

(c) What gas mileage corresponds to the worst 2.5% of all cars?

Answer #2

answered by: anonymous

The Environmental Protection Agency (EPA) fuel economy estimates
for automobile models tested recently predicted a mean of 24.8 mpg
and a standard deviation of 6.2 mpg for highway driving. Assume
that a Normal model can be applied.
a) Draw the model for auto fuel economy. Clearly label it,
showing what the 68-95-97 Rule predicts. Use StatCrunch, Excel, or
Minitab.
b) In what interval would you expect the central 68% of autos to
be found?
c) About what percent of autos...

A certain car model has a mean gas mileage of 31 miles per
gallon (mpg) with astandard deviation 3 mpg. A pizza delivery
company buys 43 of these cars. What is theprobability that the
average mileage of the fleet is greater than 30.7 mpg?

A certain car model has a mean gas mileage of 31 miles per
gallon (mpg) with a standard deviation 3 mpg. A pizza delivery
company buys 43 of these cars. What is the probability that the
average mileage of the fleet is greater than 30.7 mph

In its Fuel Economy Guide for 2014 model vehicles, the
Environmental Protection Agency gives data on 1160 vehicles. There
are a number of high outliers, mainly hybrid gas-electric vehicles.
If we ignore the vehicles identified as outliers, however, the
combined city and highway gas mileage of the other 1134 vehicles is
approximately Normal with mean 22.8 miles per gallon (mpg) and
standard deviation 5.3 mpg.
The quintiles of any distribution are the values with cumulative
proportions 0.20, 0.40, 0.60, and...

Fuel efficiency, measured in miles per gallon, for many vehicles
follows a symmetric and bell shaped distribution. Suppose the city
driving fuel efficiency of a 2009 Honda Odyssey has an average of
17mpg with a standard deviation of 2.2 mpg. What percentage of 2009
Honda Odysseys have a fuel efficiency between 12.6mpg and
19.2mpg?
Answer:???

A Ford Focus manual transmission gets an average of 28 miles per
gallon (mpg) in city driving with a standard deviation of 1.6 mpg.
Assume that gas mileage is normally distributed.
a) If a Focus is selected at random, what is the probability
that it will get more than 31 mpg?
b) What is the probability that a randomly selected Focus will
get between 20 and 30 mpg?
c) What is the probability that a randomly selected Focus will
get...

Suppose you buy a new car whose advertised mileage is 23 miles
per gallon (mpg). After driving your car for several months, you
find that its mileage is 18.5 mpg. You telephone the manufacturer
and learn that the standard deviation of gas mileages for all cars
of the model you bought is 1.24 mpg.
a. Find the z-score for the gas mileage of your car, assuming
the advertised claim is correct.
b. Does it appear that your car is getting...

The highway
miles per gallon rating of the 1999 Volkswagen Passat was 31 mpg
(Consumer Reports, 1999). The fuel efficiency that a driver obtains
on an individual tank of gasoline naturally varies from tankful to
tankful.
Suppose the mpg
calculations per tank of gas vary normally with a mean μ = 31 mpg
and standard deviation σ = 3 mpg.
According to
the Central Limit Theorem, what would be the value of the mean of
the sampling distribution if we...

Currently, the mean miles per gallon for a Nissan Sentra is 35.0
mpg. After making improvements, engineers found that for 23
randomly selected cars, the average miles per gallon is 36.8 with a
standard deviation is 4.7. Assume that the samples come from normal
populations. Find the ?-value for testing the claim that the mean
miles per gallon has increased after making these improvements.
(A) 0.040
(B) 0.079
(C) 0.960
(D) 0.096

In its Fuel Economy Guide for 2014 model vehicles, the
Environmental Protection Agency gives data on 1160 vehicles. There
are a number of high outliers, mainly hybrid gas-electric vehicles.
If we ignore the vehicles identified as outliers, however, the
combined city and highway gas mileage of the other 1134 vehicles is
approximately Normal with mean 22.8 miles per gallon (mpg) and
standard deviation 5.3 mpg. The quintiles of any distribution are
the values with cumulative proportions 0.20, 0.40, 0.60, and...

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