Final answer:
The profit margin ratio is affected by pricing policies, cost structure, and product profitability, but not directly by sales volume.
Step-by-step explanation:
Changes in the profit margin ratio may stem from varying factors; however, they do not directly signify changes in the sales volume. The profit margin ratio is a measure of a company's average profit or profit margin, calculated by dividing profit by the quantity of output produced. Factors that can influence this ratio include changes in the pricing policy, which affects the revenue per unit sold, and cost structure, encompassing both fixed and variable costs that affect the total and average costs of production. Additionally, changes in product profitability can be reflected in this ratio, as it indicates how much profit each product or service is contributing relative to its costs. In contrast, sales volume pertains to the quantity of products sold and would impact total profit but not directly the profit margin ratio.