Final answer:
The average age of residents in assisted living is typically greater than 70 but less than 80 years old, aligning with the 'middle-old' category of the elderly population in the U.S.
Step-by-step explanation:
The average age of all assisted living residents is typically greater than 70 but less than 80 years old. Considering the life-stage subgroups in the United States, where the "young-old" are categorized as between sixty-five to seventy-four years, the "middle-old" as seventy-five to eighty-four years, and the "old-old" as over eighty-five years, most assisted living residents fall into the "middle-old" category. Furthermore, demographic shifts in the U.S. have shown an increase in the elderly population, with a significant proportion living beyond the age of sixty-five and requiring different levels of support, including assisted living.