International Journal of Exercise Science 14(3): 1090-1098, 2021. The purpose of this investigation was to observe the effects of normobaric hypoxia on accumulated oxygen deficit (AOD) with evaluation using both Bayesian and Frequentist analyses. Eighteen recreationally active men performed a graded exercise test (GXT) in normobaric normoxia (N; FiO2~20%) and normobaric hypoxia (H; FiO2~14%) to determine peak power output (PPO). Time to exhaustion trials were later conducted at 110% and 120% PPO under both N, and H. AOD and %AN (% anaerobic energy contribution) were calculated in three conditions: N, H, and H using the N regression equation (HN). Bayesian repeated measures ANOVA revealed differences in AOD and %AN between regression equations while Frequentist Repeated measures ANOVA revealed non-significant differences for AOD (p = .148) and %AN (p = .150). Using predicted oxygen consumption extrapolated from a normoxic environment during exercise in hypoxia may lead to overestimation of AOD and %AN with a Bayesian approach and contrasting results using frequentist statistics