Using data from e(+)e(-) annihilation into hadrons, taken with the OPAL det
ector at LEP at the Z pole between 1991 and 1995, we performed a simultaneo
us measurement of the colour factors of the underlying gauge group of the s
trong interaction, C-F and C-A, and the strong coupling, alpha (s). The mea
surement was carried out by fitting next-to-leading order perturbative pred
ictions to measured angular correlations of 4-jet events together with mult
i-jet related variables. Our results,
C-A = 3.02 +/- 0.25(stat.) +/- 0.49(syst.), CF = 1.34 +/- 0.13(stat.) +/- 0
.22(syst.),
alpha (s) (M-Z) = 0.120 +/- 0.011(stat.) +/- 0.020(syst,),
provide a test of perturbative QCD in which the only assumptions are non-ab
elian gauge symmetry and standard hadronization models. The measurements ar
e in agreement with SU(3) expectations for C-F and C-A and the world averag
e of alpha (s)(M-Z).