The random measurement error \(X\) of a meter has a normal distribution with mean 0 and variance \(\sigma^{2}\), i.e., \(X=N\left(0, \sigma^{2}\right)\). It is known that the percentage of measurements, which deviate from the 'true' value by more than \(|0.4|\), is \(80 \%\). Use this piece of information to determine \(\sigma\).