  We have obtained single-epoch optical photometry for 201 quasars, taken from
the FIRST Bright Quasar Survey, which span a wide range in radio loudness.
Comparison with the magnitudes of these objects on the POSS-I plates provides
by far the largest sample of long-term variability amplitudes for
radio-selected quasars yet produced. We find the quasars to be more variable in
the blue than in the red band, consistent with work on optically selected
samples. The previously noted trend of decreasing variability with increasing
optical luminosity applies only to radio-quiet objects. Furthermore, we do not
confirm a rise in variability amplitude with redshift, nor do we see any
dependence on radio flux or luminosity. The variability over a radio-optical
flux ratio range spanning a factor of 60,000 from radio-quiet to extreme
radio-loud objects is largely constant, although there is a suggestion of
greater variability in the extreme radio-loud objects. We demonstrate the
importance of Malmquist bias in variability studies, and develop a procedure to
correct for the bias in order to reveal the underlying variability properties
of the sample.
