a$.$What are fixed$$ costs? Assume that the linear relationship assumption is appropriate within the relevant range of $0$ to $14,000$ units. The company uses the$$ high$-$low method to separate total costs by cost behavior.

b$.$What is the contribution margin per$$ unit?

c$.$Is it appropriate to use this information to project operating income at $17,000$units$?$ Why or why$$ not?

d$.$For which decisions is this information useful when costs are broken down by cost$$ behavior?

e$.$What other internal and external information would be relevant to understand profit$$ predictions, pricing, performance$$ evaluation, and customer$$ demand?