Final answer:
The categorization of elderly age groups involves varying definitions by chronological age and implications for eligibility for benefits, with 65 often marked as the beginning of old age. AARP includes those 50 and older, reflecting changing work and retirement trends. Demographic age divisions aid in assessing population distributions and planning for future needs.
Step-by-step explanation:
The question pertains to understanding how different age groups are defined and particularly focuses on the categorization of the elderly population. According to various sources mentioned, the definition of "elderly" can on physical health or chronological age, with entities such as the U.S. government and the World Health Organization providing slightly varying perspectives. For instance, age definitions often classify individuals aged sixty-five and over as elderly, triggering eligibility for specific federal benefits. Organizations like AARP identify fifty years as the threshold for membership, subtly shifting the perception of who is considered older or retired, especially as many continue to work beyond the traditional retirement age.
The demarcation of age categories has implications for social norms and entitlements. For example, turning eighteen typically signifies reaching adulthood with associated legal responsibilities, while sixty-five is conventionally the starting point of old age recognized by eligibility for senior benefits. The categorization of population age groups also allows for demographic analysis, as shown by the U.S. Census Bureau's tracking of population age distribution, depicted in Table A4 and Figure A6, showing the division among children, working-age adults, and the elderly for selected years.