11 0/0.8 points A concert promoter is forecasting this year's attendance for one of his concerts based on the following historical data: Year Four Years ago Three Years ago Attendance 10,000 12,000 18,000 20,000 Two Years ago Last Year What is this year's forecast using exponential smoothing with alpha = .2, if last year's smoothed forecast was 15,000? 20,000 19,000 17,500 16,000 15,000