"The table below shows the sales of a gaming console for the first 6 months of the year 2011. The forecaster uses the weighted average model to determine the forecasts. He assumes a 40% weight for the most recent reading, 30% weight for the second most recent reading, 20% for the third most recent reading, and 10% for the fourth most recent reading. Month:Units Sold - 1:33, 2:33, 3:21, 4:20, 5:30, 6:33. Using the given data, calculate the value of the mean absolute deviation."