Table 4. OIRD values of respiratory frequency and peak inspiratory airflow in hypercapnic conditions and the several types of statistical tests.

	Arrb2 -/-OIRD median or mean (95% CI)	Arrb2+/- mean (95% CI)	Arrb2 +/+ mean (95% CI)	Arrb2 -/- vs. Arrb2 +/+ (Mann-Whitney or unpaired t-test, two tail)	Arrb2 -/- vs. Arrb2 +/+(95% CI)	Kruskal-Wallis orOne-way anova	Two-way Anova - regression(interaction)
Freq.	0.66	0.63 (0.55→0.71)	0.70 (0.60→0.80)	P = 0.52 (MW)	–0.11→0.15	0.16 (KW)	0.45
PIF	0.66 (0.64→0.68)	0.68 (0.61→0.77)	0.69 (0.64→0.72)	P = 0.46 (t)	–0.04→0.08	0.86 (anova)	0.96