TABLE 1.

Rounding off age, here by 0.75 years, leads to errors in the predicted values for forced expiratory volume in 1 s (FEV₁) and forced vital capacity (FVC)

Age, years (rounded off)	Males		Females
	FEV1	FVC	FEV1	FVC
3 versus 3.75	−2.8	−3.4	−2.9	−3.6
10 versus 10.75	−1.3	−1.4	−2.6	−2.7
15 versus 15.75	−3.4	−2.9	−3.4	−2.9
50 versus 50.75	+0.4	+0.4	+0.6	+0.7
85 versus 85.75	+0.7	+0.5	+0.9	+1.0

Data presented as % error