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Exponential distribution calculator

The exponential distribution calculator returns tail probabilities and quantiles for a waiting time with rate λ, whose mean is 1/λ.

What is Exponential distribution calculator?

The exponential describes the waiting time between Poisson events, and is the only continuous distribution without memory — the chance of surviving another hour does not depend on how long you have already waited.

That memorylessness makes it the constant-hazard special case of the Weibull, and the baseline against which an increasing or decreasing hazard is judged in survival analysis.

When should I use Exponential distribution calculator?

  • Finding the probability that a wait exceeds a given time.
  • Reading the median or another quantile of a waiting time.
  • Sanity-checking a constant-hazard assumption.

What data does it need?

Distribution parameters, plus a value x, a tail probability p, or both.

What does it report?

For x: the density or exact probability and each tail. For p: the lower, upper and two-tailed critical values.

What does it assume?

  • None — this evaluates a distribution rather than testing data against one.

See also