As a firm begins to operate outside the relevant range, the accuracy of cost estimates for fixed and variable costs:

As a firm begins to operate outside the relevant range, the accuracy of cost estimates for fixed and variable costs tends to decrease.

Here's why:

1. The relevant range is the volume of activity over which the assumed cost relationship is valid for the normal operations of a firm. It's the range of activity where the total fixed costs remain constant and the variable cost per unit remains constant.

2. Fixed costs are costs that do not change with the level of output in the short run. Examples include rent, salaries, and insurance. Within the relevant range, these costs are predictable and do not change.

3. Variable costs, on the other hand, change with the level of output. Examples include direct materials and direct labor. Within the relevant range, the cost per unit of output remains constant, but the total variable cost changes with the level of output.

4. When a firm operates outside the relevant range, the assumptions about fixed and variable costs may no longer hold. Fixed costs may increase or decrease, and the variable cost per unit may change. This makes cost estimates less accurate.

5. For example, if a firm significantly increases its output, it may need to rent additional space or hire more managers, which increases fixed costs. Or the firm may be able to negotiate bulk discounts for direct materials, which decreases the variable cost per unit.

6. Therefore, when a firm operates outside the relevant range, managers should be cautious about using cost estimates based on the relevant range. They may need to gather additional data and adjust their cost estimates.