Information flow in communication networks and real-time systems grows rapidly. One of the notable examples for this kind of flow is Voice over IP (VoIP) streaming. This real-time traffic is sensitive to the delay jitter of the packets. This work addresses the statistical characteristics of delay jitter. Analytical expressions for delay jitter and its absolute value are derived using the transformations of probability distributions (Laplace transforms) approach. Some surprising and non-intuitive results are explored. An algorithmic methodology for the delay jitter calculations is suggested for treating cases where the Laplace transforms approach is not applicable due to heavy tailed probability distributions. Finally, a few examples are provided to demonstrate the use of the mathematical methods presented.