Exponential distribution

Returns either the probability density or the cumulative distribution of a random variable. This function is used to model the time between events. For example, it can be used to estimate the probability that an automatic-teller machine will take no more than one minute to deliver requested cash.

Syntax

ExponentialDistribution <Cumulative> (x, lambda)

Where:

Cumulative is a logical value that determines the form of the function:

• If Cumulative=0 (default), it returns the cumulative distribution.
• If Cumulative=1, it returns the probability density.

x is the value of the function.

lambda is the value of the parameter.

Expression

For probability density:

For cumulative distribution:

Usage Notes

The following conditions are invalid:

• Either x or lambda is nonnumeric
• x<0
• lambda £ 0