Engineering Board Exam Reviewer · Hypergeometric, Poisson, and Geometric Distributions · medium

Calls arrive at a switchboard at an average rate of 3 per minute (Poisson). What is the probability of exactly 2 calls in a given minute?

  1. 0.0498
  2. 0.224
  3. 0.1494
  4. 0.4481

Answer

B. 0.224

Solution

P(2)= e-3322!=9/2e-3=0.2240.

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