The integral of the area under the Gaussian curve is often used to
report errors in terms of a confidence level in percent. For example,
in the value reported as 64 ± 8, 8 is equal to s and represents
68% of the area under the appropriate Gaussian curve for N=64.
It may be stated as the value one is 68% confident of obtaining if
the measurement is repeated. Traditionally, many of CANBERRA’s
MCAs have used 1.65 s, which corresponds to a 90% confidence
level. Probable error is often used, which corresponds to a 50%
confidence level. These can be user-set to other values, such as: