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Recap chapter 18
1.
When cars are manufactured the gas mileage will vary from car to car.
Suppose that the
mean gas mileage for all cars of a certain model is 25 miles per gallon (mpg) and the
standard deviation of the mileages for this model car is 2 mpg.
Assume that the distribution
of the mileages for all cars of this model is a normal distribution.
A) Write a sentence that gives the meaning of μ in this example. (NO NUMBERS)
B)
Sketch the distribution gas mileages of the individual cars of the model. Label the axis
with the mean and mean ± SD
C) About 95% of the individual cars of this model will have gas mileage between
____ and _____.
(Put your answer with your work.)
D) Suppose 15 cars of this model are randomly selected and their mean gas mileage is
calculated. If many such samples were drawn sketch the sampling distribution of
the sample means.
E) 95% of random samples of 15 cars of this model will have mean gas mileage
between ____ and _____.
(Put your answer with your work.)
F) If a random sample of 15 cars of this model is selected what is the probability that
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This note was uploaded on 10/18/2011 for the course STA 2023 taught by Professor Shaw during the Fall '11 term at Valencia.
 Fall '11
 Shaw
 Standard Deviation

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