Reconstruction error η of the 21 cm signal power spectrum calculated as an average over a multipole range, defined here as 30 ≤ ℓ ≤ 270, on each frequency channel of a dataset with MD80, considering two different numbers of realizations (N_realis = 10 and N_realis = 50). The value in parentheses is the average error over all channels in each dataset. The mean error for the N_realis = 10 case is and for the N_realis = 50 case is .