1.a) The values of the magnetic moment are given in nuclear magnetons. So the only thing we have to do is divide the numbers by their spins to obtain the g-factors. For the ground state this is g =-0.5948861/(1/2) = -1.1897722. For the 245 keV level, we have g = -0.766/(5/2) = -0.3064.
1.b) The free electron has spin 1/2 and a magnetic moment of 1 bohr magneton. So g = (mu/mu_B)/I = 2.
1.c) The free neutron has also a spin of 1/2. So its magnetic moment is mu = g * I * mu_N = -1.913 mu_N