Various methods and apparatuses for measuring a state parameter of anindividual using signals based on one or more sensors are disclosed. In oneembodiment, a first set of signals (1600) is used in a first function todetermine how a second set of signals is used in one or more second functionsto predict the state parameter (1620). In another embodiment, first and secondfunctions (1610) are used where the state parameter or an indicator of thestate parameter may be obtained from a relationship between the first functionand the second function. The state parameter may, for example, includecalories consumed or calories burned by the individual. Various methods formaking such apparatuses are also disclosed.
