The mass index formula predicts trend reversals by calculating the range between high and low prices for each period. A bulge in the index line signals a possible trend reversal. You can use a 9-day Exponential Moving Average Formulato determine whether the bulge is a buy or sell signal.
The following example takes input from Series1's Y value for the high and low prices, respectively, (Series1:Y,Series1:Y2), and outputs the mass index on Series3 (Series3:Y). It uses an accumulation period of 30 days and a moving average period of 12 days.