The monthly demand for heating oil (in litres) at a supermarket for the last 5 years is shown below: Sales JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 2016 3000 4000 4000 6000 5000 7000 8000 7000 11000 13000 15000 9000 2017 4000 5000 4000 6000 6000 8000 4000 9000 13000 12000 17000 11000 2018 3000 6000 6000 4000 5000 7000 8000 11000 16000 16000 19000 9000 2019 6000 5000 5000 3000 6000 8000 13000 15000 17000 17000 21000 13000 2020 6000 3000 4000 3000 8000 7000 9000 11000 19000 21000 23000 9000 (1) (11) Plot the demand data on an Excel Spreadsheet. What do you notice about the demand pattern? (4 marks) Forecast the monthly demand for heating oil for the year 2021. You should use the most appropriate forecasting method. Submit the Excel Spreadsheet as a separate file (12 marks) Examine the demand forecasting method by evaluating the forecast errors. Use any two (2) measures of error. Show the performance of the forecasting with the help of a plot. (12 marks) (111)