Steven buys a pair of scissors instead of getting a haircut. he belives the scissors will last for a long time, while the haircut will only last a few weeks. in this case, scissors is a good, while the haircut is a service. why is the haircut considered a service here?

Automobile fuel efficiency is often measured in miles that the car can be driven per gallon of fuel (mpg). heavier cars tend to have lower fuel efficiencies (lower mpg ratings). which variable (weight or fuel efficiency) is most naturally considered the explanatory (predictor) variable in this context?