Statistical properties of the faint early-type galaxies sample: possible effects of evolution

Early-type galaxies from CfA catalogue were assotiated with IRAS FSC sources. In given sample IR and optical properties were used to obtain some classification of these objects. The existance of significant classes can be evidence of presence one main type of the dust in each galaxy. Physical interpretation of obtained classes was discussed. The dust mass in two classes of galaxies can be calculated using evolution modelling. In this case we can obtain a estimations for chemical composition and initial mass function in these galaxies.