Fig. 6.

Global COVID-19 epidemic trajectory between two hemispheres during the period between Feb 2020 and Feb 2023. Dotted line shows 95% confidence intervals. Robustness of fitting model was evaluated by use of the adjusted coefficient of determination (adj R²), sum of squares due to error (SSE), root mean square deviation (RMSE), and F value using one-way analysis of variance (ANOVA) with the level of significance at α = 0.05. Means and variances were compared with Bonferroni and Tukey’s multiple tests. The red line represents the population ratio of the N hemisphere to global with 70.18%, published by the United Nations Population Division (UNPD) in 2019 (Table S4)