Test of cosmic variance and uncertainties of X_LAE for our MUSE observations using GALICS mocks of the bursty SF model. Top panel: X_LAE vs. z for M₁₅₀₀ ∈ [ − 21.75; −18.75], at z <  5. In order to better compare GALICS with our observations and to provide a more accurate estimate of cosmic variance, we use slightly different EW cuts for the model. We replace the 45 Å cut with 46 Å, 48 Å, and 46 Å cuts at z ≈ 3.3, 4.1, and 4.7, and we replace the 65 Å cut with 53 Å, 52 Å, and 49 Å at the same redshifts. With these cuts, the values of X_LAE from MUSE (violet and orange circles at for EW(Lyα) ≥ 45 Å and EW(Lyα) ≥ 65 Å) and GALICS (solid lines) match. Middle panel: relative upper 1σ uncertainties of X_LAE vs. z for M₁₅₀₀ ∈ [ − 21.75; −18.75], at z <  5. The relative 68% percentiles of X_LAE (field-to-field variance) measured among 100 GALICS mocks are indicated by violet and orange circles with soloid lines for EW(Lyα) ≥ 45 Å and EW(Lyα) ≥ 65 Å, respectively. The 68% percentile includes both of the cosmic variance and statistical error. The statistical errors estimated from BPCI are shown by violet and orange crosses. The MUSE uncertainties (estimated from BPCI including completeness correction effects) for EW(Lyα) ≥ 45 Å and EW(Lyα) ≥ 65 Å are indicated by violet and orange circles, respectively. Bottom panel: relative lower 1σ uncertainties of X_LAE vs. z for M₁₅₀₀ ∈ [ − 21.75; −18.75], at z <  5. The symbols are the same as those in the middle panel. For visualization purposes, we slightly shift the points along the x-axis.