Final answer:
The plantwide predetermined overhead rate for Mickley Company cannot be determined from the information given.
Step-by-step explanation:
The plantwide predetermined overhead rate for Mickley Company can be determined by dividing the estimated total manufacturing overhead costs by the estimated total amount of the allocation base. In this case, the allocation base is the direct labor-hours. We are not provided with the estimated total manufacturing overhead costs or the estimated total direct labor-hours, so the predetermined overhead rate cannot be determined from the information given. Therefore, the correct answer is option 3) Cannot be determined.