Fig. 1
From: A pilot study of hot-wire, ultrasonic and wedge-bellows spirometer inter- and intra-variability
Differences in measurements between hot-wire, ultrasonic and wedge-bellows spirometers for FVC and FEV1. Bland–Altman plots with mean difference ± 1.96SD (95% limits of agreement) for hot-wire compared to ultrasonic spirometers (a), for wedge-bellows compared to ultrasonic spirometers (b), and for hot-wire compared to wedge-bellows spirometers (c). ***p < 0.001, n.s. not significant. p values are derived from linear mixed models analysis with the spirometer as fixed effect and a random intercept by subject, and are adjusted for multiple comparisons (Bonferroni correction). Significance level is set at 0.05