Final answer:
The false statement is that only one staff member is needed to operate a mechanical lift when transferring a resident; typically, at least two trained staff members are recommended for safety.
Step-by-step explanation:
The statement false about using a mechanical lift to transfer a resident is: "There must be at least one staff member to operate the lift." This is incorrect because, for safety reasons, it is generally recommended that at least two trained staff members should be present when operating a mechanical lift to ensure the safe transfer of the resident. All the other statements regarding the condition of the lift, the trained status of the operator, and the selection of the sling based on specific needs are correct and represent best practices in using a mechanical lift.