This thesis presents a study of W±Z diboson production with the ATLAS experiment at the LHC. The measurements are made using 20.3fb⁻¹ of data collected during proton-proton collisions produced at a centre-of-mass energy of √s = 8 TeV. Final states with three leptons and missing transverse energy are considered. The first study of the polarisation of the W boson in such events is presented. This study provides a cross-section independent method by which to study anomalous gauge boson couplings. The estimated sensitivity of this measurement to anomalous gauge boson couplings will therefore also be presented. Also discussed, are measurements of the W±Z production cross-section and limits on anomalous gauge boson couplings. Finally, a study is presented which assess the impact of extending the inner-detector tracker to |η| = 4.0. This was considered for the ATLAS upgrade program. The effect of such an extension was studied for multiple final states, including the W±Z inclusive and VBS analyses as well as the WWW triboson analysis.