A measure of the amphipathicity of an ¿-helix. Each amino acid side chain is assigned a value, positive or negative, according to its hydrophobicity. These values are used to weight vectors for each residue as they are displayed around the helix. The summation of the vectors is the hydrophobic moment, ¿_M. Mean hydrophobicity, H, is the sum of the hydrophobicity values divided by the number of residues.