555The modification on the properties of a nucleon in a nuclear medium related to the EMC effe~t, critical density, incompressibility, Roper reasonance, etc., have been investigated with interesting conclusions in the context of the statistical model. .The incompressibility of a nucleon may play an important role as nuclear matter is compressed. Due to the finite size of nucleon, we come across a stituation when nucleons press against one another as nuclear matter is compressed considerably. As each individual nucleon undergoes squeezing, the knowledge of the incompressibility of a nucleon turns out. to be essential. Bhaduri et al.l) have suggested that in the ground state, the nucleon compressibility lies in the range 900-1200 Me V. Further an important interpretation widely accepted for the recently found EMC effect is supposed to be the increase in the size of a nucleon in a nuclear medium. J affe 2 ) has presented an excellent review on EMC effect and has discussed its many fascinating aspects. Mathieu et al. 3 ) have estimated an increase in the radius of a nucleon in nuclear matter in the context" of colour dielectric model and have found an enhance· ment in radius 15% in the neighbourhood of deconfinement region. In a subsequent analysis Mathieu et al. 4 ) have also investigated some properties of a nucleon in nuclear matter in the framework of a flux tube model of a hadron.In the present work we have investigated some properties of a nucleon in the statistical model considering nucleons constituting a nucleus to be embedded in a nuclear medium and some interesting results are obtained. In the statistical mode1 5 )-8) a nucleon is considered to consist of a cloud of virtual qdh, q2 ih, q~ ifa pairs in addition to the valence quarks ql, q2, q3 so that val~nce quarks only determine the quantum number of a colourless baryon. The real and virtual quarks of a particular flavour are regarded as identical and indistinguishable so that they form a statistical ensemble Of a weakly interacting Fermi gas. To take into account the effect of many·body interaction which a valence quark experiences in its encounter with a large number of its virtual quark and antiquark pairs, we assume that each valence quark moves in an average background field. With the above consideration we have derived an analytical form of the square of wavefunction of a hadron as 5 )(1)where ro is the radius parameter of a nucleon. This 1¢(r)12 is free from interaction parameter and constituent quark mass and has been derived without reference to any dynamical equation of motion.Considering a nucleon consisting of quark-diquark linked by flux tube, the