  Deriving the distribution of binary parameters for a particular class of
stars over the full range of orbital separations usually requires the
combination of results from many different observing techniques (radial
velocities, interferometry, astrometry, photometry, direct imaging), each with
selection biases. However, Cepheids---cool, evolved stars of $\sim$$5\,
M_\odot$---are a special case because ultraviolet spectra will immediately
reveal any companion star hotter than early type A, {\it regardless of the
orbital separation}. We have used {\it International Ultraviolet Explorer}
(\IUE) UV spectra of a complete sample of all 76 Cepheids brighter than V=8 to
create a list of {\it all 18} Cepheids with companions more massive than $2.0\,
M_\odot$. Orbital periods of many of these binaries are available from
radial-velocity studies, or can be estimated for longer-period systems from
detected velocity variability. In an imaging survey with the {\it Hubble Space
Telescope} Wide Field Camera 3, we resolved three of the companions (those of
$\eta$ Aql, S Nor, and V659 Cen), allowing us to make estimates of the periods
out to the long-period end of the distribution. Combining these separations
with orbital data in the literature, we derive an unbiased distribution of
binary separations, orbital periods, and mass ratios. The distribution of
orbital periods shows that the $5\, M_\odot$ binaries have systematically
shorter periods than do $1\, M_\odot$ stars. Our data also suggest that the
distribution of mass ratios depends both on binary separation and system
multiplicity. The distribution of mass ratios as a function of orbital
separation, however, does not depend on whether a system is a binary or a
triple.
