  The radial acceleration relation (RAR) of late-type galaxies relates their
dynamical acceleration, $g_\text{obs}$, to that sourced by baryons alone,
$g_\text{bar}$, across their rotation curves. Literature fits to the RAR have
fixed the galaxy parameters on which the relation depends -- distance,
inclination, luminosity and mass-to-light ratios -- to their maximum a priori
values with an uncorrelated Gaussian contribution to the uncertainties on
$g_\text{bar}$ and $g_\text{obs}$. In reality these are free parameters of the
fit, contributing systematic rather than statistical error. Assuming a range of
possible functional forms for the relation with or without intrinsic scatter
(motivated by Modified Newtonian Dynamics with or without the external field
effect), I use Hamiltonian Monte Carlo to perform the full joint inference of
RAR and galaxy parameters for the Spitzer Photometry and Accurate Rotation
Curves (SPARC) dataset. This reveals the intrinsic RAR underlying that
observed. I find an acceleration scale $a_0=(1.19 \pm 0.04 \, \text{(stat)} \pm
0.09 \, \text{(sys)}) \: \times \: 10^{-10}$ m s$^{-2}$, an intrinsic scatter
$\sigma_\text{int}=(0.034 \pm 0.01 \, \text{(stat)} \pm 0.01 \, \text{(sys)})$
dex (assuming the SPARC error model is reliable) and weak evidence for the
external field effect. I make summary statistics of all my analyses publicly
available for future SPARC studies or applications of a calibrated RAR, for
example redshift-independent distance measurement.
