Table 2 Co-integration results using the Phillips-Ouliaris (PO) test between daily infection data and daily death data with a positive seven-day lag in the FW time period. The null hypothesis indicates that there is no co-integration, and we use a 95% confidence level. DD* represents Death Data with a positive lag of seven days. Note: a – represents statistically significant co-integration in FW; b – represents statistically significant co-integration in TW1; c – represents statistically significant co-integration in TW2; d – represents statistically significant co-integration in TW3

From: A data-driven approach to study temporal characteristics of COVID-19 infection and death Time Series for twelve countries across six continents