Firebaugh and his colleagues measured the age, total family income, and general happiness of individuals aged 20 to 64, generally considered the working life span for most Americans.

• 格伦·菲尔鲍和他的同事们对20岁到64岁的不同人群的年龄、家庭收入和幸福感进行了调查。这个年龄段通常被认为是大多数美国人一生中参加工作的时间。