QCD studies with e+e- annihilation data at 172-189 GeV

We have studied hadronic events fi om e(+)e(-) annihilation data at centre-of-mass energies of root s = 172. 183 and 189 GeV. The total integrated luminosity of the three samples, measured with the OPAL detector, corresponds to 250 pb(-1). We present distributions of event shape variables, charged particle multiplicity and momentum, measured separately in the three data samples. From these we extract measurements of the strong coupling a,, the mean charged particle multiplicity (n(ch)) and the peak position xi(0) in the xi(p) = ln(1/x(p)) distribution. In general the data are described well by analytic QCD calculations and Monte Carlo models. Our measured values of alpha(s), (n(ch)) and xi(0) are consistent with previous determinations at root s = M(Z)o.