Exponential Distribution

These functions give you access to the exponential distribution. The exponential distribution arises, for example, when events occur, on the average, every mu seconds. If they are independent, the distribution of intervals between events is exponential with mean mu. For more information about Fathom's distribution functions, click here.

exponentialDensity(x, mu, min)

exponentialCumulative(x, mu, min)

exponentialQuantile(x, mu, min)

 mu = the mean of the distribution
min
= the minimum value

The density, cumulative, and quantile functions for the exponential distribution.

Only the x (the independent variable) is required. If you supply mu, it must be positive.

The mu acts as a scaling factor. The min is a horizontal translation.

defaults: mu = 1, min = 0.

You may also draw random values from this distribution: 

randomExponential(mu, min)

A random value drawn from that distribution.

Here are some plots to help you understand the meaning of the mu parameter. The exponential is like the geometric distribution in that it declines monotonically. This distribution's mu is like the reciprocal of the geometric p.

See also statistical functions (for mean( ) and its cousins).