  Using the LOWZ and CMASS samples of the ninth data release (DR9) from the
SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), I investigate
properties of star forming galaxies and AGNs. The CMASS sample seriously
suffers from the radial selection effect, even within the redshift 0.44<z<0.6,
which will lead to statistical conclusions in the CMASS sample being less
likely robust. In the LOWZ sample, the fraction of star-forming galaxies is
nearly constant from the lowest density regime to the densest regime; the AGN
fraction is also insensitive to the local environment. In addition, I note that
in the LOWZ sample, stellar mass and stellar velocity dispersion distributions
of star forming galaxies and AGNs are nearly same.
