Statistics 简明教程
Statistics - Exponential distribution
指数分布或负指数分布表示泊松过程事件之间的时间概率分布。在泊松过程中,事件以一个恒定的平均速率连续且独立地发生。指数分布是一个特定的伽马分布。
Exponential distribution or negative exponential distribution represents a probability distribution to describe the time between events in a Poisson process. In Poisson process events occur continuously and independently at a constant average rate. Exponential distribution is a particular case of the gamma distribution.

Probability density function
指数分布的概率密度函数表示为:
Probability density function of Exponential distribution is given as: