  We report on precision measurements of the frequency of the radial
compression mode in a strongly interacting, optically trapped Fermi gas of Li-6
atoms. Our results allow for a test of theoretical predictions for the equation
of state in the BEC-BCS crossover. We confirm recent quantum Monte-Carlo
results and rule out simple mean-field BCS theory. Our results show the
long-sought beyond-mean-field effects in the strongly interacting BEC regime.
