d) If June's estimated machine-hours total 2,400, what are the total estimated costs of the Machining Department? (1 mark) e) Consider variable cost per machine hour "b" calculated in (a) above. If it takes two (2) machine hours to produce one (1) unit and total 1,200 units are produced, then calculate total variable cost. (1 mark) (1 mark) What is the main advantage of using the regression method for cost estimation? d) If June's estimated machine-hours total 2,400, what are the total estimated costs of the Machining Department? (1 mark) e) Consider variable cost per machine hour "b" calculated in (a) above. If it takes two (2) machine hours to produce one (1) unit and total 1,200 units are produced, then calculate total variable cost. (1 mark) (1 mark) What is the main advantage of using the regression method for cost estimation