Electroweak parameters of the Z0 resonance and the standard model

The four LEP experiments have each performed precision measurements of Z0 parameters. A method is described for combining the results of the four experiments, which takes into account the experimental and theoretical systematic errors and their correlations. We apply this method to the 1989 and 1990 LEP data, corresponding to approximately 650 000 Z0 decays into hadrons and charged leptons, to obtain precision values for the Z0 parameters. We use these results to test the standard model and to constrain its parameters.