Estimate and Forecast COVID -19 Pandemic in Victoria, South Australia, and Capital Territory of Australia

Australia is one among the countries which neutralized the spread of COVID 19. Now they are waiting to reopen the state after locked down for several months. Objectives of the study are to estimate and forecast the number of infected cases of COVID -19 in Victoria (Vic), South Australia (SA) and Australian Capital Territory (ACT), as they might be guidelines for reopening the states. The daily confirmed cases of COVID-19 of the Vic, SA, and ACT for the period of 22^nd January 2020 to 15^th June 2020 were obtained from the World Health Organization (WHO) database. Both descriptive and inferential statistics were used for data analysis. Time series plots, Auto Correlation Functions (ACF), and Partial Auto Correlation Functions (PACF) were used to examine the pattern of the series. The Auto-Regressive Integrated Moving Average (ARIMA) and Linear Trend Models were tested to forecast the pandemic. The Anderson Darling test, ACF, and Ljung-Box Q (LBQ)-test were used to test the validation criterion and fit the model. The forecasting ability of the models was assessed by two measurements of errors; Route Mean Square Error (RMSE), and Mean Absolute Deviation (MAD) in both model fitting and verification process. It is concluded that there is a 99% possibility that population means of daily infected cases in Vic, SA, and ACT are 9, 2, and 1 consecutively. The patterns of daily infected cases in SA and ACT have reached the zero level. The number of infected cases in Vic would tend to zero by 2^nd October 2020.