The degree of accuracy of linear measurement is usually expressed as the ratio of the probable error and the measured distance. For example, if there is a probable error of ± 0.05 m in a measured distance of 584.65 m, the degree of accuracy is 1 in 11700 as explained below.
The ratio is always reduced in a fraction with the numerator as unity.
These days the trend is to express the degree of accuracy as the ratio of the standard error (s) instead of the probable error. Thus
