Table 2. Prevalence levels and weights of the volunteer sample groups in comparison with the healthcare visits population with low, l, medium, m, and high, h, contact rates.

Sample groups, i	Prevalence, p(i,t)	Weight, w(i,t)
Healthcare visits	0.64	25.6
Volunteers with high contact rates	0.08	3.20
Volunteers with medium contact rates	0.04	1.60
p0	0.025	1.0
Volunteers with low contact rates	0.02	0.80