Cosmic chronometers, Pantheon+ supernovae, and quasars favor coasting cosmologies over the flat $\mathrm{\Lambda }$CDM model

We test and compare coasting cosmological models with curvature parameters $k=\{-1,0,+1\}$ in $H_0^2{c}^{-2}$ units and the flat $\mathrm{\Lambda }$CDM model by fitting them to cosmic chronometers (CC), the Pantheon+ sample of type Ia supernovae (SNe), and standardized quasars (QSOs). We used the $\mathtt{\text{emcee}}$ code for fitting CC data, a custom Markov Chain Monte Carlo implementation for SNe and QSOs, and Anderson-Darling tests for normality on normalized residuals for model comparison. Best-fit parameters are presented, constrained by data within redshift ranges $z\le 2$ for CCs, $z\le 2.3$ for SNe, and $z\le 7.54$ for QSOs. Coasting models, particularly the flat coasting model, are generally favored over the flat $\mathrm{\Lambda }$CDM model. The overfitting of the flat $\mathrm{\Lambda }$CDM model to Pantheon+ SNe and the large intrinsic scatter in QSO data suggest a need to refine error estimates in these datasets. We also highlight the seemingly fine-tuned nature of either the CC data or ${\mathrm{\Omega }}_{\mathrm{m},0}$ in the flat $\mathrm{\Lambda }$CDM model to an $H_1=H_0$ coincidence when fitting $H(z)=H_{1}z+H_0$, a natural feature of coasting models.