The prices of securities are constantly changing during market hours. You can track price changes at any point in time using real-time market data, but that can only tell you where the price has been and where it is at any point in time. In order to try and predict where the price of a security may be moving, you can look at a number of different factors which are grouped together in the discipline of stock analysis.
Technical analysis looks at the historic and current price movement and trends in a security. By comparing movements in price, volume, and demand & supply factors, technical traders can estimate where the price could move in the future. One of the most commonly used ways to compare these movements is by using a study.