Time Series Analysis Of Monthly Sales Of Petrol In A Petroleum Filing Station: A Case Study Of Conoil Plc, 25 Aba Road, Umuahia, Abia State.:- Azubuike, Kelvin N.

ABSTRACT

 Time series approach was used to study sales data in a filling station. The data were collected fi'om a Conoil Petrol Station in Umuahia. The disti'ibution of Autocorrelation and Partial Autocorrelation functions suggested a Seasonal Autoregressive Integrated Moving Average Model, given by SARIMA (1,1,1)x(1, 0, 0)i2. The parameters of the SARIMA were estimated with statistical software (MINITAB). The following mathematical model was obtained: yt = 0.1567yt.i + 0.6604yt_i2 - 0.1035yt.i3 + et - 0.9832eM. From the above model, estimates and two years forecast were obtained. The correlogram of the residual explain a pure white noise process for the error ofthe model.