Saved Which of the following statements is true with respect to the degree of operating leverage (DOL)? 8 Multiple Choice It is calculated as the ratio of contribution margin (CM) to operating Income, at each level of output For most firms, it is relatively constantin ount as sales volume changes. It provides a simple way to estimate the change in total fixed cost for a given change in sales volume. It is calculated as the amount of operating income where t= the income tax rate It can be calculated and used by manufacturing but not service firms