Path diagrams of the confirmatory factor model. Rectangles Observed variables (items), ellipses latent variables (factors), values on the single-headed arrows standardized factor loadings, values on the double-headed arrows correlation coefficients. Model fitness: comparative fit index = 0.912, normed fit index = 0.905, root mean square error of approximation = 0.082 (90 % confidence interval 0.078–0.088)