A two-step method and apparatus are provided for automatically characterizing the spatial arrangement among the data points of a time series distribution in a data processing system. The method and apparatus utilize a Cartesian grid to determine: the number of cells in the grid containing at least one input data point of the time series distribution; the expected number of cells which would contain at least one data point in a random distribution in said grid; and an upper and lower probability of false alarm bracketing the expected value utilizing a discrete binomial probability relationship in order to analyze the randomness of the input. A statistical test of significance of the sparse data is utilized to determine the existence of noise and signal. The probability of distinguishing noise from signal is increased by comparing the parts of the method.