Additional file 3 of Systematic comparison of four point-of-care methods versus the reference laboratory measurement of hemoglobin in the surgical ICU setting: a cross-sectional method comparison study

Additional file 3: Figure S1. Quantile-Quantile (Q-Q) plot was performed to visually evaluate data normality by comparing two probability distributions of theoretical and sample quantiles. Most data points lay close to a linear diagonal line with some points presented within the 95% confidence interval (the grey color band).