Fig. 6. Bland-Altman limits of agreement (LOA) analysis using a ratio transformation. 17,18(Top ) The ratio of the airway measurement of V̇CO²to the stoichiometric value was plotted against the average of both values. At each ethanol infusion level, V̇CO²was the average of five replicate consecutive measurements. The LOA (mean ± 1.96 SD) for V̇CO²were 0.1 ± 4.7%, where 95% of all points lay within these limits. (Bottom ) In the same analysis for V̇O², the LOA were 1.1 ± 5.7%. Compared with figure 5, where LOA were calculated by plotting the difference between the airway measurement of V̇CO²(or V̇O²) and the stoichiometric value versus  the average of both values, the ratio plot corrected for the greater scatter of the differences at higher values of either V̇CO²or V̇O²and provided a better reflection of the accuracy of the data.