The American Automobile Association (AAA) reported that the national average price of regular gasoline on May 17, 2018 was $2.90 per gallon. The following data show the price per gallon of regular gasoline for 15 randomly selected stations in your area. These data can also be found in the Excel file titled gas prices.xlsx.

$2.98 $2.84 $2.99 $2.90 $2.96
$2.98 $2.76 $2.96 $2.86 $2.89
$2.83 $2.71 $2.89 $2.99 $2.83

a. Construct a 90% confidence interval to estimate the average price per gallon of gasoline in the state.

b. Do the results from this sample validate AAA’s findings?

c. What assumptions need to be made about this population?