Signal prediction is about more than predicting the next value of the stock market.
It has applications in many different fields. For example, it can be used for compression, especially in the case of speech signals. Speech signals have a high degree of periodicity, making them easier to predict. Basic signal prediction takes past and current values of the signal and weights them with different coefficients to estimate the next value of the signal. The difference between the original signal and the predicted signal is called the prediction error.