can you explain without using excel

501 2- After tallying the receipts for their first year of operation, the owners of the Taco Barn are encouraged. Sales of their artisanal tacos, made from such exotic ingredients as ground beef, cheese, and beans, have been strong and seem to give hope to the coming year. Taco sales by month are shown in the table. Month Sales January 474 February 485 March April 588 May 579 June 673 July 594 August 679 September October 699 November 732 December 732 Armed only with his fingers, the owner decides that the safest forecasting approach is a weighted moving average using 0.8, and 0.2 for the most recent two. Generate a forecast for the year using this technique and then calculate forecast errors using MAPD. What is the mean absolute percentage deviation for this forecasting approach? 608