out metallicity and RV cuts as follows. The left panel of Figure 5 illustrates the \[Fe/H\] distribution for three different subsamples of stars. The first, shown as the black dot-dashed line, represents the distribution of derived metallicities for the 1547 stars with available estimates of \[Fe/H\] along the line of sight to M 13. Note that this distribution includes numerous stars that cannot be considered members of the cluster, as they cover a much wider range of \[Fe/H\] than might be expected if they were drawn exclusively from the cluster member population. The dot-dashed line in the right panel of Figure 5 shows the RV distribution of these same stars.

The red dashed line in the left panel of Figure 5 is the distribution of \[Fe/H\] for the 296 likely members selected from the spectroscopic sample as described above. We obtain a Gaussian fit to the [*highest peak*]{} of the distribution of these stars (solid blue line in Figure 5), and obtain an estimate of the mean ($<$\[Fe/H\]$>$) and standard deviation ($\sigma$) for this distribution. Similar fits are obtained for the distribution of RVs for the likely members shown in the right panel of Figure 5. On the basis of 