For those who are looking for explanation: No measurement is 100% exact. For example when a temperature is measured, the outcome depends on the quality of the measuring system, the procedure of the measurement, the operator skill, the environment, and other effects. If the temperature would be measured several times, using the same method and under the same circumstances, in general different temperatures would be obtained each time. (This assumes the measuring system has sufficient resolution e.g. 20,123°C instead of 20°C). The average of the repeated measurements, shown here as “Measured value” would present the best estimate of the true value. The measurement uncertainty is an absolute value, representing the “bandwith” (e.g 0,1°C) indicating the quality of the measurement result meaning that if the presented value would be 20°C, the true value could be in the range of 19,9 – 20,1°C.