The Tokai-to-Kamioka (T2K) experiment is a long baseline neutrino oscillation experiment. T2K uses a beam of muon neutrinos (neutrino beam mode) or antineutrinos (antineutrino beam mode) produced at the Japan Proton Accelerator Research Complex and directed towards the Super-Kamiokande detector to study neutrino oscillations in two ways. One is the disappearance of muon neutrinos as they oscillate to other flavors of neutrinos, while the other is the appearance of electron neutrinos that have oscillated from muon neutrinos. In addition to the far detector, Super-Kamiokande, a suite of detectors is set close to the neutrino source to probe the beam composition prior to the neutrinos oscillating.Within the neutrino oscillation analysis, uncertainties due to the neutrino beam flux and the cross section of neutrinos serve as the largest sources of error on the oscillation parameters. By including data from the Near Detector at 280 m (ND280), the uncertainties on the flux and cross section can be constrained beyond what the data at the far detector can do on its own. This work describes the near detector maximum likelihood fit and how it is used to constrain uncertainties for the oscillation analysis.For this thesis, new data samples were included in the near detector fit so that the antineutrino beam mode samples would be treated in the same way as the neutrino beam mode samples. The results are consistent with those seen before; however, they also indicate that certain checks should be updated when the new neutrino interaction model is available before fully transitioning to the new samples.Additionally, tests were performed to study the effect of alternative cross section models on the near detector fit. These studies showed that there is not enough freedom in the current cross section model to fully describe any effects on the data if the underlying cross section differed from the current model.
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