Exponential distribution is another most significant and extensively used continuous probability distribution. Exponential random variable is frequently used to model the time interval between two events. Some illustrations of random variables that generally conform to model by means of exponential
distribution are presented below.
• Arrival time between two customers.
• Time between two messages.
• Time between telephone calls received by a customer service.
• Time between customers who are arriving to the checkout lane of the supermarket.
• Time between two failures of a certain mechanical device.