The following audit procedures relate to tests of details of balances for inventory:
For raw materials inventory or finished goods inventory that is purchased in final form, select a sample of inventory items from inventory files and examine underlying supporting documents from the purchasing process agreeing amounts (or cross reference inventory work papers to purchases work papers where this step was performed).

Required:
For these procedures explain how the steps might be extended so the evidence contributes to:
(1) ICFR audit related to purchasing
(2) ICFR audit related to inventory
(3) ICFR audit related to sales
(4) Auditor’s inventory observation.