Final answer:
The percentage of time allocated to preventive maintenance, also known as the 'duty cycle,' varies based on the activity and sector. For air conditioner maintenance, budgeting 1.1 hours per technician might be too low due to the standard deviation of one hour. In furnace repair, the longest 25% of repairs take at least 3.375 hours, representing the 75th percentile.
Step-by-step explanation:
When discussing the percentage of time allocated to preventive maintenance, we're implicitly referring to the concept of the duty cycle. A duty cycle indicates the percentage of time that a particular piece of equipment is active or, in this case, the time spent on maintenance as opposed to other tasks. In the context of servicing air conditioners and furnace repairs, understanding the average time required and the distribution of those times becomes essential for planning purposes.
For air conditioners, if a technician averages one hour per unit with a standard deviation of one hour, planning to budget 1.1 hours per technician may be insufficient, especially considering the variability implied by the standard deviation. Additionally, for furnace repairs, knowing that the longest 25 percent of repair times take at least 3.375 hours means that this is the 75th percentile of repair times. Hence, 75 percent of the repairs are expected to be completed in 3.375 hours or less.
In a broader context, job sectors such as natural resources, construction, and maintenance aggregate a considerable portion of their work time to maintenance tasks, represented here by 16.3%. This percentage is indicative of the importance placed on preventive and ongoing maintenance in these sectors.