T-test both groups
Differences DF T Valor Pr>/t/
pO2 LA-pO2 300 37 2.01 0.0515
pO2 AI-pO2 600 35 -0.87 0.3876
pO2 AI-pO2 900 34 -2.90 0.0065
pO2 AI-pO2 1200 34 -5.88 <0001
Table 3: T-Student for different pO2 values in both groups.