Density and refractive index data in the binary mixtures {xCH(3)COOCH(3) + (1 - x)CH3CH2C(OH)(CH3)(2)} and {xCH(3)OH + (1 - x)CH3CH2C(OH)(CH3)(2)} and the ternary mixture {x(1)CH(3)COOCH(3) + x(2)CH(3)OH + (1 - x(1) - x(2))CH3CH2C(OH)(CH3)(2)} are presented at T = 298.15 K over the whole range of mole fractions and atmospheric pressure, These results are used to calculate excess molar volumes and changes of refractive index of mixing. The calculated quantities are further fitted to the Redlich-Kister and the Cibulka equations to estimate the binary and ternary interaction parameters, respectively, and standard deviations from the regression lines. To compare the physical and derived properties we applied several estimation methods. A comparison is made in terms of excess molar volumes and ternary contribution to these properties by variation of the number of methyl groups in the carbon that has the hydroxyl group.