Assuming a Gaussian distribution with a standard deviation S, illustrated in Figure C-1, about 98,8 percent of all movements fall within boundaries of ± 2,5·S (i.e. within a swathe of width of 5·S).
Commission Directive (EU) 2015/996 of 19 May 2015 establishing common noise assessment methods according to Directive 2002/49/EC of the European Parliament and of the Council (Text with EEA relevance)
Assuming a Gaussian distribution with a standard deviation S, illustrated in Figure C-1, about 98,8 percent of all movements fall within boundaries of ± 2,5·S (i.e. within a swathe of width of 5·S).