Parameter estimated by multiple linear regression analysis models for FVC, FEV₁, and FEF_25–75% as dependent variables and sex, age class, height, and weight as independent variables.

<p>^aThis parameter is set to zero because it is redundant</p><p>*β coefficients indicate how much a dependent variable changes per each unit variation of the independent variable, taking into account the effect of the other independent variables in the model. For categorical variables, β coefficients represent the effect of moving from the “reference” category (^a) to another</p><p>Data are shown for 2,393 asymptomatic children.</p><p>Parameter estimated by multiple linear regression analysis models for FVC, FEV₁, and FEF_25–75% as dependent variables and sex, age class, height, and weight as independent variables.