The department manager using a combination of methods has forecast sales of toasters at a local department store. Calculate the MAD for the manager's forecast. Compare the manager's forecast against a naive forecast. By how many units on average does manager's forecast differ from a naive forecast?

$\backslash$table$[[$Month$,$Unit Sales,Manager's$],[$Jorecast$,,],[$February$,52,],[$March$,61,],[$April$,73,],[$May$,66,],[$June$,51,],[$July$,47,50],[$August$,44,55],[$September$,30,52],[$November$,74,55]]$