A drive through candy shop kept a record of the number of cans of drink it sells over a 3-week period: Week 1 Week 2 Week 3 Mon Tues Wed Thurs Fri Mon Tues Wed Thurs Fri Mon Tues Wed Thurs Fri 18 22 7 15 19 23 9 8 16 21 23 10 10 16 Required: a) Compute a 4-point moving average and Centre them marks) b) Draw a time series graph and super impose the trend line over it marks) c) Comment on the trend direction and speed b) Assuming an additive model, completely decompose the time series marks)