Select ALL the possible causes of an unfavorable overhead rate variance. The purchasing manager purchased cheap, low quality direct materials to help his chances of a bonus. The cost of indirect materials has increased due to a limited supply The factory janitor received a pay raise Overtime is required for assembly workers to finish a rush job Poor scheduling requires a rush order of direct materials Poor maintainance of machines requires more lubricant Cost of employee benefits for assembly workers has increased The production manager failed to provide adequate training of his assembly line workers Using higher-skilled workers than expected on the assembly line A recent tariff on fossil fuels has increased the cost of electricity