Binned Hubble parameter measurements and the cosmological
  deceleration-acceleration transition
  Weighted mean and median statistics techniques are used to combine 23
independent lower redshift, $z<1.04$, Hubble parameter, $H(z)$, measurements
and determine binned forms of $H(z)$. When these are combined with 5 higher
redshift, $1.3\leqslant z \leqslant 2.3$, $H(z)$ measurements the resulting
constraints on cosmological parameters, of three cosmological models, that
follow from the weighted-mean binned data are almost identical to those derived
from analyses using the 28 independent $H(z)$ measurements. This is consistent
with what is expected if the lower redshift measurements errors are Gaussian.
Plots of the binned weighted-mean $H(z)/(1+z)$ versus $z$ data are consistent
with the presence of a cosmological deceleration-acceleration transition at
redshift $z_{\rm da}=0.74 \pm 0.05$ \citep{farooq3}, which is expected in
cosmological models with present-epoch energy budget dominated by dark energy
as in the standard spatially-flat $\Lambda$CDM cosmological model.
