Dow Theory will predict the market trend. It will mainly study about the Demand and Supply. When Demand is more, it is time for Buy. When supply is more, it is time for Sell. For identifying the trend, we require minimum two years data points. The sequence will be Higher Bottom-Higher Top and Lower Top-Lower Bottom, which denotes buy and sell signal respectively. The trend will be valid for 2 to 3 months only.
We can identify the Supply zone and Demand zone using Dow Theroy.