All of the above reports assumed a typical set of functions,
such as polynomials, and residual errors were studied
according to the order of the function or the number of
calibration points. However, it is unclear whether the
assumed set of functions is the best one for a typical type
of thermometers, no matter how good the fittings look.
Therefore, the calibration efficiency of the sensor can not
be discussed on the same basis for different types of sensors,
such as carbon glass thermometers and platinum
resistance thermometers.