So your selection of stocks will be determined by your investing style. We need volatility. In this type of fast, action-packed trading, you have to be prepared to lose more than you invest, and to be able to get out of a losing position quickly before the losses become big losses. Momentum traders thrive on volatility in the market. To them, all the answers are in the price movement.
Momentum traders are essentially day traders who treat the stock market as one big casino.
They are a sadistic breed that achieves a 'high' from extreme activities - like people who get a thrill out of bungee jumping and walking on a tight rope across the KL Twin Towers. They are not interested in what business the company is in. Their only interest is in the price movement of the stocks they're watching. Volatility is the name of the game. It lets you see all the bid and offer prices for each stock, hence a day trader can tell at a glance not only what the market is doing, but what it's about to do.