Average is a type of Ratio. Average is related to Like. Like is related to Hang. Hang is a type of Decorate. 
you are likely to find Fork in/at/on Back. Back is a type of Lie. one thing you do when you Lie is Injury. you are likely to find Injury in/at/on Accident. 
Ratio <--IsA-- Average <--RelatedTo--> Like <--RelatedTo--> Hang --IsA--> Decorate 
Fork --AtLocation--> Back --IsA--> Lie --HasSubevent--> Injury --AtLocation--> Accident 