... Using the uvby -photometry and proper motion data for about 5500 F stars within 80 pc from the Sun, we have studied velocity ellipsoid parameters and obtained the following results. 1) The sizw of all wllipsoid semiaxes increase systematically for groups of stars with the decrease of both temperature (at constant metallicity) and metallicity (at constant temperature). ... As a result, each of the three parameters - temperature, metallicity and velocity dispersion - is an age indicator. ...