3. A can opener manufacturer has had monthly sales for a seven-month period as follows: Month Sales (000 units) February 19 March 18 April 15 May 20 June 18 July 22 August 20 a. Plot the data b. Forecast September's sales volume using every one of the following techniques: i. A linear trend equation ii. A four-month moving average iii. iv. A weighted average using 0.50 for August, 0.30 for July and 0.20 for June The nave approach C. Which method seems to be the least appropriate? Why? 20 marks