expcdf (Statistics Toolbox)

Exponential cumulative distribution function (cdf).

Syntax

P = expcdf(X,MU)

Description

P = expcdf(X,MU) computes the exponential cdf at each of the values in X using the corresponding parameters in MU. Vector or matrix inputs for X and MU must have the same size. A scalar input is expanded to a constant matrix with the same dimensions as the other input. The parameters in MU must be positive.

The exponential cdf is

The result, p, is the probability that a single observation from an exponential distribution will fall in the interval [0 x].

Examples

The median of the exponential distribution is µ*log(2). Demonstrate this fact.

mu = 10:10:60; 
p = expcdf(log(2)*mu,mu)
p =
    0.5000    0.5000    0.5000    0.5000    0.5000    0.5000

What is the probability that an exponential random variable will be less than or equal to the mean, µ?

mu = 1:6;
x = mu;
p = expcdf(x,mu)
p =
    0.6321    0.6321    0.6321    0.6321    0.6321    0.6321

ewmaplot expfit