Tasks

Properties of Inter-arrival Times

Instructions

Theory

  • Exponential Distribution: For a Poisson process with an average event rate of \(\lambda\), the time between consecutive events (the inter-arrival time, \(T\)) is an Exponentially distributed random variable. Its PDF is given by \(f(t) = \lambda e^{-\lambda t}\).
  • Independence: A key property of the Poisson process is that its inter-arrival times are independent. The time you wait for the next event does not depend on how long you've already waited.
  • Testing Independence: We can visually test for independence by creating a scatter plot of consecutive inter-arrival times, \((T_i, T_{i+1})\). If the times are independent, the points should form a random "cloud" with no discernible pattern. The slope of a best-fit line through this cloud should be close to **zero**.

Procedure

  • Use the slider to set the Poisson rate (\(\lambda\)) and press **Start**.
  • Observe the timeline as events appear in real-time. The timeline shows absolute time and will pan as the simulation progresses.
  • The Distribution Analysisplot compares the histogram of waiting times to the theoretical Exponential PDF (orange line).
  • The Independence Analysis plot shows the scatter plot. Observe how the best-fit line remains nearly horizontal (slope ≈ 0).

Inter-arrival Time Simulation

2.0

Arrivals Timeline

Distribution Analysis

Independence Analysis

Observations