  We validate the baryonic Tully Fisher (BTF) relation by exploring the Tully
Fish er (TF) and BTF properties of optically and HI-selected disk galaxies. The
data includes galaxies from: Sakai et al. (2000) calibrator sample; McGaugh et
al. (2000: MC2000) I-band sample; and 18 newly acquired HI-selected field dwarf
galaxies observed with the ANU 2.3m telescope and the ATNF Parkes telescope
from Gurovich's thesis sample (2005).
  As in MC2000, we re-cast the TF and BTF relations as relationships between
baryo n mass and W_{20}. First we report some numerical errors in MC2000. Then,
we c alculate weighted bi-variate linear fits to the data, and finally we
compare the fits of the intrinsically fainter dwarfs with the brighter galaxies
of Sakai et al. (2000). With regards to the local calibrator disk galaxies of
Sakai et al. (2000), our results suggest that the BTF relation is indeed
tighter than the T F relation and that the slopes of the BTF relations are
statistically flatter th an the equivalent TF relations. Further, for the
fainter galaxies which include the I-band MCG2000 and HI-selected galaxies of
Gurovich's thesis sample, we calc ulate a break from a simple power law model
because of what appears to be real c osmic scatter. Not withstanding this
point, the BTF models are marginally better models than the equivalent TF ones
with slightly smaller reduced chi^2.
