"In the financial industry, there are three main approaches to investment: the fundamental approach, where strategies are based on fundamental economic principles, the technical analysis approach, where strategies are based on past prices behavior, and the mathematical approach where strategies are based on mathematical models and studies. The main advantage of technical analysis is that it avoids model specification, and thus calibration problems, misspecifi- cation risks, etc. On the other hand, technical analysis techniques have limited theoretical justifications, and therefore no one can assert that they are riskless, or even efficient."
As I understand, mathematical models allow you to find arbitrage and value derivatives fairly. They explain the pricing of securities which allows you to see if the security is undervalued or overvalued. They are also used for forecasting future prices and most models incorporate risk. Technical indicators are less complicated but can still be useful.
Technical analysis is a specific kind of quantitative analysis mainly based on charts. But quantitative analysis also includes other types of analysis- correlations, regression analysis, combining fundamental analysis with technical analysis etc.
Three econometricians went out hunting, and came across a large deer. The first econometrician fired, but missed, by a metre to the left. The second econometrician fired, but also missed, by a metre to the right. The third econometrician didn't fire, but shouted in triumph, "We got it! We got it!"
============ Risk- manager hit the target, even if one measures in yards[36'']; have plenty of ammo, plenty of time if possible, to score