First we note the wide chemical shift range of the signals. Note also that the signal we attribute to the methyl group is approximately a 1:3:3:1 quartet, the methylene approximately a 1:2:1 triplet, and the aromatic CHs approximately 1:1 doublets. The intensity ratios suggest this is due to coupling and the multiplicities that it is due specifically to coupling of the spin 1/2 13C with the spin 1/2 protons and nothing else (ie the 2nI+1 rule, I being the spin number). Before we move on to discuss how this coupling may be useful to us, let us remind ourselves of how the coupling arises. Remember the energy level diagram of one spin 1/2 nucleus in a magnetic field;