  We consider the statistics of the scattering coefficient S of a chaotic
microwave cavity coupled to a single port. We remove the non-universal effects
of the coupling from the experimental S data using the radiation impedance
obtained directly from the experiments. We thus obtain the normalized, complex
scattering coefficient whose Probability Density Function (PDF) is predicted to
be universal in that it depends only on the loss (quality factor) of the
cavity. We compare experimental PDFs of the normalized scattering coefficients
with those obtained from Random Matrix Theory (RMT), and find excellent
agreement. The results apply to scattering measurements on any wave chaotic
system.
