Signed relative error
= Signed relative error
{title2=$\varepsilon=(x_{\mathrm{approx}}-x)/x$}
The signed relative error is $\varepsilon=(x_{\mathrm{approx}}-x)/x$ for a nonzero reference $x$. Its <absolute value> is the <relative error>. For a positive reference, a negative <signed relative error> means underestimation, and a positive one means overestimation. For a negative reference that interpretation reverses, so retain the displayed definition when interpreting its sign.