Question

3. A company that supplies gasoline nationwide reports that the average price per gallon of regular gasoline is $ 8,150, with a standard deviation of $ 428. There are 750 gasoline stations in the country. Suppose a random sample from 40 gas stations is selected.

b. What is the mean or expected value of the sample distribution of the means?
c. What is the standard error of the sample distribution of the means?
d. Write the syntax for the sample distribution of the means.

e. Find the probability that in the sample of 40 stations the sample average is less than $ 8050.
F. Find the probability that in the sample of 40 stations the average price of a gallon of current gasoline will be greater than $ 8245.

Answer 1

Let , , n=40

b. The mean of the sample distribution of the mean is ,

c. The standard error of the sample distribution of the mean is ,

d.

e.

; From standard normal distribution table

f.

; From standard normal distribution table