A Researcher Wanted to Determine If Using an Octane Booster $X _ { 1 }$

question 96

Multiple Choice

A researcher wanted to determine if using an octane booster would increase gasoline mileage. A random sample of seven cars was selected; the cars were driven for two weeks without the booster and two weeks with the booster. Use the definitions of $X _ { 1 }$ and $X _ { 2 }$ as given in the table. Consequently, $D = X _ { 1 } - X _ { 2 }$ .


Compute the standard deviation of the differences.

• A) 0.84
• B) 0.13
• C) 0.11
• D) 0.78

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Definitions:

Confidence Estimate

Confidence estimate is a range of values, derived from sample data, that is likely to contain the value of an unknown population parameter, expressed with a certain level of confidence.

Mayoral Election Race

A competitive political event in which candidates vie for the mayor's office in a city, town, or municipality.

Majority of Votes

A voting outcome in which more than half of the votes cast are in favor of a particular option or candidate.

Margin of Error

An indicator of the precision of an estimate, showing how much the estimated value could vary from the true value.