adopted in the SED fitting (Shapley et al. use a constant star formation history), and in part from the slightly different color selection criteria adopted in this paper, compared to previous works (see also end of this section).\
Following the approach used in P07 we compare the properties of $LBG_L$ to those of $LBG_N$. We find that the masses of $LBG_N$ are larger than the masses of $LBG_L$ and the galaxies without emission line are somewhat older. The median values with relative uncertainties, are reported in Table 1 and the distributions are shown in Figure \[fig:fig1\]. To assess the differences between the two samples in the physical parameters and their statistical significance, we perform a non-parametric Kolmogorov-Smirnov (K-S) test on the age and mass distributions. We find that the difference is indeed highly significant for the mass distribution (P=0.000), while only weakly significant for the age distributions (P=0.136).\
The difference between the two samples at z$\sim 3$ is much less pronounced than at higher redshift: at z$\sim$4 the masses of $LBG_N$ were 5 times larger than the emitters, while in the present work, the difference is only around a factor of 2. Similarly, for the ages, the difference was larger 