MODELING AND FORECASTING USING ARIMA: An Empirical Study of GDP in Sri Lanka.

An autoregressive integrated moving average (ARIMA) model is useful to analyze time-series data either for better understanding or forecasting future points in the series. This paper aims and forecast GDP of Sri Lanka based on Box-Jenkins approach annual from 1971 2021. Box ? Jenkins technique a relatively advanced time series method it applied this at million US$ Lanka. The study attempt using an appropriate model. After testing stationarity data, were stationary first difference after calculating logarithm data. From Correlogram ACF, we determined ARIMA which (1,1,1) GDP. (1, 1, 1) was seen as superior fit estimating Lanka?s US$. According values predicted, Lankan shows higher growth trend next few years 2022 2030 However, result only predicted value.