Table 1. Characteristics of the sample compared with the Hong Kong population.

Characteristics	Sample	Population structurea	Effect sizeb
Age group
18–34 years	29.1%	33.1%	0.09
35–54 years	41.8%	41.2%
≥55 years	28.4%	25.7%
Gender
Female	53.7%	52.3%	0.03
Male	46.3%	47.7%
Marital status
Single	31.4%	32.4%	0.02
Married/formerly married	67.3%	67.6%
Education
Primary or below	15.8%	25.4%	0.30
Secondary	49.7%	51.6%
Tertiary or above	33.9%	23%
Birth place
Hong Kong	68.0%	60.3%	0.16
Other places	31.5%	39.7%

^aBased on 2006 Hong Kong by-census (Census & Statistics Department HKSAR).

^bEffect sizes are calculated via the formula , where and are the observed proportions in the i'th category from the by-census data and survey data, respectively.