Final answer:
The Units of Production method of depreciation for assets with varying in-service time and explains that the difference in IQR of FTES between two time periods could be due to changes in policies or enrollment patterns.
Step-by-step explanation:
The method used when an FA's (Fixed Asset's) in-service time varies from year to year is generally referred to as the Units of Production method of depreciation. This method is useful when the service provided by the asset varies from one year to the next, as it allows for depreciation to be based on the actual usage or production levels rather than simply the passage of time.
In order to understand the differences in the Interquartile Range (IQR) for different time periods, such as the IQR of the Full-Time Equivalent Students (FTES) for 1976-1977 through 2004-2005 compared with 2005-2006 through 2010-2011, one would have to account for changes in policies, enrollment patterns, demographics, and educational trends over those periods. A significantly different IQR suggests that there was greater variation in one time period over the other, perhaps due to changes in enrollment stability or the implementation of new educational programs or funding models.