Question

The average cost of a gallon of unleaded gasoline in Greater Cincinnati was reported to be \$2.41 (The Cincinnati Enquirer, February 3, 2006). During periods of rapidly changing prices, the newspaper samples service stations and prepares reports on gasoline prices frequently.
Assume the standard deviation is \$.15 for the price of a gallon of unleaded regular gasoline, and recommend the appropriate sample size for the newspaper to use if they wish to report a margin of error at 95% confidence.
a. Suppose the desired margin of error is \$.07.
b. Suppose the desired margin of error is \$.05.
c. Suppose the desired margin of error is \$.03.

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