The correct order is:
- The cars from Company B have a higher MODE of highway fuel efficiency than Company A.
- The cars from Company A have higher MEDIAN highway fuel efficiency than Company B.
- The cars from Company A have higher MEDIAN highway fuel efficiency than Company B.
- The cars from Company A have higher MEAN highway fuel efficiency than Company B.
- The cars from Company A have higher MEAN highway fuel efficiency than Company B.
- The cars from both companies have the same mean, median, and mode for highway fuel efficiency.