EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH CERN-EP-2000-148 OPAL PR 328 30 Novemb er 2000 Precise Determination of the Z Resonance Parameters at LEP: "Zedometry" The OPAL Collaboration Abstract This final analysis of hadronic and leptonic cross-sections and of leptonic forward-backward asymmetries in e+ e- collisions with the OPAL detector makes use of the full LEP 1 data sample comprising 161 pb-1 of integrated luminosity and 4.5 Ч 106 selected Z decays. An interpretation of the data in terms of