Final answer:
The 20-year-old has the median age in the group. In statistical terms, the median is the middle value in a list of numbers sorted in ascending order. Early adulthood, which includes the 20s, is a phase of peak physical performance and fertility.
Step-by-step explanation:
The question refers to identifying the descriptive statistical term for the 20-year-old among a group of five people with specific ages. Given the ages 32, 28, 20, 18, and 17, the 20-year-old has the median age. This is because when the ages are listed in ascending order (17, 18, 20, 28, 32), the age in the middle is 20, which is the definition of the median in statistics.
Early adulthood is a phase that coincides with the ages 20s to early 30s. During this stage, people often reach peak physical performance and fertility in females is also at its peak.
According to population studies, the age group of 18-64 is growing and will continue to do so, whereas the youngest age group remains largely static. Interestingly, the population chart indicates a significant increase in the older age brackets, notably those 65-84, which has implications for societal resources and economic development.