In general,errors in temperature measurement derie from two fundamental sources. The first source of errors derives from uncertain information about the temperature of the sensor itself. Such uncertainties can result from random interpolation errors, calibration systematic errors, or a host of other error sources. Instrument and procedural uncertainty in the sensor temperature can be reduced by improved calibration or by changes in the measuring snd recording instrument. However, errors in temperature measurement can still occur even if the temperature of the sensor was measured exactly.In such cases, the probe does not sense accurately the temperature it was intended to measure.