Fuel consumption is commonly measured in miles per gallon. The Environmental Protection Agency designed new fuel consumption tests to be used starting with 2008 car models. Listed below are randomly selected amounts by which the measured MPG ratings decreased because of the new 2008 standards. For example, the first car was measured at 16 mi/gal under the old standards and 15 mi/gal under the new 2008 standards, so the amount of the decrease is 1 mi/gal. Would there be much of an error if, instead of retesting all older cars using the new 2008 standards, the mean amount of decrease is subtracted from the measurement obtained with the old standard?

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