Quantifying the evidence for the current speed-up of the Universe with
  low and intermediate-redshift data. A more model-independent approach
  We reconstruct in this paper the deceleration and jerk parameters as
functions of the cosmological redshift from data on cosmic chronometers (CCH),
baryon acoustic oscillations (BAOs), and the Pantheon+MCT compilation of
supernovae of Type Ia (SnIa). The reconstruction is carried out with the
Weighted Function Regression method, previously introduced by G\'omez-Valent &
Amendola (2018). It improves the usual cosmographic approach by automatically
implementing Occam's razor criterion. This makes our procedure to be more free
of model and parametrization dependencies than many other analyses in the
literature. The reconstructed functions are fully compatible with the
predictions for the concordance model. In addition, we also discuss the
confidence level at which we can claim that the Universe (assumed to be flat,
homogeneous and isotropic) is currently accelerating. According to Jeffreys'
scale and jargon, we find moderate evidence in favor of such speed-up using the
data on SnIa+CCH, and very strong one when we also use data on BAOs. The
measured current value of the deceleration parameter in the latter case reads
$q_0\sim -0.60\pm 0.10$, and for the deceleration-acceleration transition
redshift we find $z_t\sim 0.8\pm 0.10$. The former is $\sim 6\sigma$ away from
$0$. This is in stark contrast, for instance, with the $\sim 17\sigma$ that are
found in the context of the flat $\Lambda$CDM even without including the BAOs
data. This indicates that cosmography and Occam's razor criterion play a
crucial role in this discussion, and that estimating the evidence for positive
acceleration only in the framework of a particular cosmological model or
parametrization is clearly insufficient.
