Table 1.

General characteristics of respondents (N = 1,515)

Variable	Category	n	%
Gender	Male	753	49.7
	Female	762	50.3
Age (years)	19-29	295	19.5
	30s	375	24.8
	40s	411	27.1
	50s	250	16.5
	≥60	184	12.1
Education level	≤ High school	958	63.2
	≥ College	557	36.8
Region	Metropolitan cities	720	47.5
	Cities	623	41.1
	Rural area	172	11.4
Household income (1000 won/month)	<2,000	347	22.9
	2,000-2,999	406	26.8
	3,000-3,999	353	23.3
	≥4,000	390	25.7
	Don’t know	19	1.3
Living style	Alone	79	5.2
	With family	1433	94.8
Experience in a clinical trial	No	1114	97.9
	Yes	24	2.1

Missing data were not included.