The dynamic behaviors of the plasma properties in a Hall effect thruster discharge channel are estimated using a physics-constrained extended Kalman filter (PC-EKF) with a zero-dimensional global plasma model. The state estimates obtained using the global plasma EKF model are augmented by experimental data, in this case a discharge current signal. The use of state estimation allows for the determination of time-resolved plasma behaviors that may be difficult to measure experimentally, such as electron temperature and bulk velocity. The model is applied to investigate the plasma behavior at various thruster operating conditions, i.e. at varying discharge voltages and discharge currents. The estimated plasma properties are used to determine the classical electron collision frequency and the anomalous electron scattering frequency, which are shown to vary in time.