“…Without considering unimodality, it is a well-known result of Chebyshev, who proved that 1/γ 2 is a tight upper bound of (16), regardless of the true distribution of w. Chebyshev's bound is found to be conservative in probabilistic interval forecast of renewable power [63], because the worst-case distribution is discrete, where unfavourable samples which are distant from the forecast get higher chances to occur. When the distribution is restricted to be unimodal, C. F. Gauss found an analytical solution of (16) [62] Pr [ w − w ≥ γσ] ≤ 4/(9γ 2 ), if γ > 2/ 3; 1 − γ/ 3, otherwise;…”