Final answer:
Both process costing and job costing methods assign costs to units, with process costing averaging costs over units for homogeneous products and job costing applying costs directly to specific jobs for customized orders. Marginal costs and total costs differ, especially due to the presence of fixed costs.
Step-by-step explanation:
The statement that both process costing and job costing assign costs to units as they proceed through the process is true. While both methods assign costs to products, the way they go about this can be different. Process costing is used for homogeneous products and assigns costs to each process or department within the production process. The costs are averaged over the units produced during the period. In contrast, job costing is used for customized orders and assigns costs directly to the specific job based on the materials, labor, and overhead used for that particular job.
It is important to note that the marginal cost of the first unit of output is not necessarily the same as the total cost. Marginal cost refers to the cost of producing one additional unit of output, whereas total cost includes all fixed and variable costs incurred up to a certain level of output. Fixed costs do not change with the level of output, while variable costs do. Therefore, if there are fixed costs involved, the marginal cost of the first unit would be different since it would include a share of those fixed costs.