Select the incorrect statement regarding the use of average unit costs.

Question $13$ options:

$1)$

Average costs should be calculated for a sufficiently long time period to capture seasonal fluctuations in costs.

$2)$

Average costs are often more relevant for decision making than are actual costs.

$3)$

Average cost information can help managers evaluate performance of the company or departments in the company.

$4)$

Cost averaging should be used only for fixed costs, and not for variable costs.