Write the Word or Phrase That Best Completes Each Statement $\alpha = 0.05$

Write the word or phrase that best completes each statement or answers the question.
-A consumer advocacy group believes a car manufacturer is falsely advertising that its new model car still gets at least 21 miles per gallon of gas. The advocacy group believes the median miles per gallon is less than 21 . Ten cars are tested. The results are given below. Test the group's hypothesis. Use $\alpha = 0.05$ .
$\begin{array} { l l l l l l l l l l } 15.8 & 13.6 & 19.8 & 14.9 & 18 & 20.2 & 23.3 & 17.9 & 12.7 & 19 \end{array}$