Given a formula y = f(x) with an absolute error in x of d x, the absolute error is d y. The relative error is d y/y. If x = f(u, v, ...), then x_i - x^_ = (u_i - u^_)(dx)/(du) + (v_i - v^_)(dx)/(dv) + ..., where x^_ denotes the mean, so the sample variance is given by s_x^2 | congruent | 1/(N - 1) sum_(i = 1)^N (x_i - x^_)^2 | = | 1/(N - 1) sum_(i = 1)^N[(u_i - u^_)^2 ((dx)/(du))^2 + (v_i - v^_)^2 ((dx)/(dv))^2 + 2(u_i - u^_)(v_i - v^_)((dx)/(du))((dx)/(dv)) + ...].

absolute error | accuracy | covariance | percentage error | precision | relative error | significant digits | variance