Please explain the connection between Product Costs and Cost of Goods sold? Where do period costs appear on an income statement? Finally, Why do we call them period costs? Why do we go through all the trouble (and it can be a lot of trouble) to keep these costs separate? Why do we need another format for the income statement? What's the purpose of the contribution margin income statement? When would it be used? Ive seen annual reports and I've never seen a contribution format income statement on one. Why not? Also, give an example of a mixed cost in your personal life? There are a lot of them