Determination of. alpha. sub s from a differential jet multiplicity distribution at SLC and PEP

We measure the differential jet multiplicity distribution in e{sup {plus}}e{sup {minus}} annihilation with the Mark 2 detector. This distribution is compared with the second order QCD prediction and {alpha}{sub s} is determined to be 0.123 {plus minus} 0.009 {plus minus} 0.005 at {radical}s {approximately} M{sub Z} (at SLC) and 0.149 {plus minus} 0.002 {plus minus} 0.007 at {radical}s = 29 GeV (at PEP). The running of {alpha}{sub s} between these two center of mass energies is consistent with the QCD prediction. The Q{sup 2} dependence of the {Lambda}{sub {ovr MS}} determination is also discussed. 21 refs., 3 figs.