  Different methods to extract the temperature and density in heavy ion
collisions are compared using a statistical model tailored to reproduce many
experimental features at low excitation energy. The model assumes a sequential
decay of an excited nucleus and a Fermi gas entropy. We first generate
statistical events as function of excitation energy but stopping the decay
chain at the first step. In such a condition the 'exact' model temperature is
determined from the Fermi gas relation to the excitation energy. From these
events, using quantum and classical fluctuation methods for protons and
neutrons, we derive temperature and density (quantum case only) of the system
under consideration. Additionally, the same quantities are also extracted using
the double ratio method for different particle combinations. A very good
agreement between the "exact" temperatures and quantum fluctuation temperatures
is obtained, the role of the density is discussed. Classical methods give a
reasonable estimate of the temperature when the density is very low as
expected. The effects of secondary decays of the excited fragments are
discussed as well.
