This experiment demonstrates two fundamental properties of a Poisson process by running a large number of simulated trials.
Objective
- To show that the inter-arrival time \(T_i\) in a Poisson process follows an Exponential distribution with PDF \(f(t) = \lambda e^{-\lambda t}\).
- To verify that consecutive inter-arrival times, \(T_i\) and \(T_{i+1}\), are statistically independent.
Understanding the Notation
Imagine events occurring on a timeline. We use the following notation to describe them:
- Event Times (ti): These are the absolute moments when events occur. For example, t1 is the time of the 1st event, and t2 is the time of the 2nd event.
- Inter-arrival Time (Ti): This is the waiting time, or the duration between consecutive events. It is defined as Ti = ti - ti-1. For example, T2 is the time that passes between the 1st and 2nd events (i.e., t2 - t1).
This experiment analyzes the properties of these inter-arrival times (Ti).
Procedure
- Set the Poisson Rate (\(\lambda\)), which is the average number of events per second.
- Choose which inter-arrival time to analyze using the dropdown (e.g., the 1st, 2nd, or 3rd). This selects the index i for Ti.
- Select the Number of Trials to run. A higher number will produce a more accurate result.
- Click "Run Simulation". The simulation will run all trials instantly.
- Analyze the Distribution: The left chart shows a histogram of the collected Ti values. Observe how closely the blue histogram matches the theoretical orange Exponential curve.
- Analyze Independence: The right chart plots pairs of consecutive inter-arrival times, (Ti, Ti+1). If the points form a random, shapeless cloud with a best-fit line slope near zero, the times are independent.