“…where ∅ = autoregressive or damping parameter; θ = moving average parameter; µ = mean value of the process; ε t = forecast error at time t, in which ε t is assumed to follow a normal (0, σ) distribution, σ = standard deviation of the process (Lee & Chae, 2016). Equation (4.1) defines an autoregressive process of order p, AR(p), 'which predicts values from previous values'; Equation (4.2) defines a moving average process of order q, MA(q), 'which accounts for previous random trends'; Equation (4.3) defines an autoregressive moving average process of order (p,q), ARMA(p,q); and Equation (4.4) defines an autoregressive integrated moving average process of order (p,q) differenced by order d, ARIMA(p,d,q) (Lee & Chae, 2016).…”