Comparison of posterior distributions using different combinations of observables i.e. only 21 cm power spectra (red), 21 cm power spectra + 21 cm-density cross-power spectra (green), and adding bias of cross-spectra (blue). The diagonal panels show the 1D posterior probability distribution, and the off diagonal panels show the joint 2D posteriors. The contours represent the 68% and 95% confidence intervals. The dashed line represents the input parameter values used to generate the mock dataset. The observational uncertainties are assumed to be 5% of the observable amplitudes in this case.