If you clean the fuel injectors of a particular car, it increases the miles per gallon by two. Letting a driver skilled at increasing mpg take the car around the course increases mpg by four. Suppose the injectors were cleaned and a skilled driver drove the car. Which outcome below represents the one in which there is no interaction between the two variables?
A) increase six mpg
B) increase four mpg or two mpg
C) increase two mpg
D) decrease by two mpg.

Question

Quizplus · Accepted Answer

There is no interaction between the two variables if the effects of cleaning the fuel injectors and having a skilled driver are additive, resulting in a total increase of six mpg (2 mpg from cleaning + 4 mpg from skilled driving).

If You Clean the Fuel Injectors of a Particular Car