Table 3.

Sample quota design

Demographic characteristics	Percentage of China's adult population*	Total quota sample size
	(%)	N = 2400
Gender
Male	51.13%	1227
Female	48.87%	1173
Age
18-29a	20.11%	483
30–39	19.10%	458
40–49	20.28%	487
50–59	18.18%	436
≥ 60	22.32%	536

^*The proportion of China's adult population was calculated using the data from China Statistical Yearbook (2019);

^a18–19-year-old population data in the "China Statistical Yearbook (2019)" was included in the 15–19-year-old population, so it was obtained by calculating the average population of each age in the 15–19 years old