The manager of a company is preparing revenue plans for the last quarter of 1993/94 and for the first three quarters of 1994/95. The data below refers to one of the main products: Required: a) Calculate the four-quarterly moving average trend for this set of data. (6 Marks) b) Calculate the seasonal factors using either the additive model or multiplicative model but not both. (8 Marks) Activate Windows c) Explain, but do not calculate how you would use the results in parts (a) and (b) of this question to forecast the revenue for the last quarter of 1993/94 and for the first three quarters of 1994/95. (6 Marks)