The table above shows the results of a controlled experiment designed to determine the effect of distance on the amount of fuel consumed by a pickup truck with the tailgate in various
positions. Based on the results of this experiment, which conclusion is NOT valid?

The truck needed the least fuel to travel a set distance when its tailgate was
all the way up.

The truck needed the most fuel to travel a set distance when its tailgate was
all the way down.
There is an association between lowering the truck's tailgate and an increase
in the amount of fuel needed to travel a set distance.

A truck owner that drives with the tailgate up will spend less money on fuel
than a truck owner that drives with the tailgate down.