Fig. 5

Second set of sampled volumes (n = 6). Comparison between operators (OP 1, OP 2 and OP 3) and methods (CEM and DM) related to RC (green line) performed on 400 μL (a), 425 μL (b), 450 μL (c), 475 μL (d) and 500 μL (e). Different letters show significant statistical differences between operators compared to RC (α = 0.05). Auxiliary Table (f) showing the operator effect of comparison between methods related to RC. Asterisks indicate to which condition one operator (*) or both (**) attended. First column: sample volume assessed. Second column: Conditional equality between RC and CEM. Third column: Conditional equality between RC and DM. Fourth column: Conditional equality between CEM and DM. Fifth column: Operator effect confirmation, assuming that DM was equal to RC or CEM (or both), at least for one operator, then the operator effect was present