You obviously havent heard of Random Walk Theory (RWT). This says that the movement on any day is statistically independent of moves on any previous days, and cant be predicted at all. RWT is held to be true by virtually all conventional economists, which is why fundamentals has such a following.
Nevertheless, just as it is aerodynamically impossible for a bumblebee to fly, us tech analyst types just keep on predictin'.
RWT has been fairly significantly modified, first by volatility theory, which says that the SIZE of moves (whether positive or negative) is correlated with the day before ; and which is one of the cornerstones of Black-Scholes; and secondly by chaos theory, which suggests that the market has a reasonably low fractal dimension and is therefore moderately predictable.
