# Distributions

<table><thead><tr><th width="165">Distribution</th><th width="135">Parameters</th><th width="185">Type/Format</th><th>Description</th></tr></thead><tbody><tr><td><code>fixed</code></td><td><code>value</code></td><td>Any real number</td><td>Draws all values exactly equal to <code>value</code></td></tr><tr><td><code>uniform</code></td><td><code>low</code></td><td>Any real number</td><td>Draws all values randomly from a uniform distribution with range <code>[low, high]</code></td></tr><tr><td></td><td><code>high</code></td><td>Any real number greater than <code>low</code></td><td></td></tr><tr><td><code>poisson</code></td><td><code>lam</code></td><td>Any positive real number</td><td>Draws all values randomly from a Poisson distribution with rate parameter (mean) <code>lam</code> (lambda)</td></tr><tr><td><code>binomial</code></td><td><code>size</code></td><td>Any non-negative integer</td><td>Draws all values randomly from a binomial distribution with number of trials (n) = <code>size</code> and probability of success on each trial (p) = <code>prob</code></td></tr><tr><td></td><td><code>prob</code></td><td>Any number in [0,1]</td><td></td></tr><tr><td><code>lognormal</code></td><td><code>meanlog</code></td><td>Any real number</td><td>Draws all values randomly from a lognormal distribution (natural log, base <em>e</em>) with mean on a log scale of <code>meanlog</code> and standard deviation on a log scale of <code>sdlog</code></td></tr><tr><td></td><td><code>sdlog</code></td><td>Any non-negative real number</td><td></td></tr><tr><td><code>truncnorm</code></td><td><code>mean</code></td><td>Any real number</td><td>Draws all values randomly from a truncated normal distribution with mean <code>mean</code> and standard deviation <code>sd</code>, truncated to have a maximum value of <code>a</code> and a minimum value of <code>b</code></td></tr><tr><td></td><td><code>sd</code></td><td>Any non-negative real number</td><td></td></tr><tr><td></td><td><code>a</code></td><td>Any real number, or <code>-Inf</code></td><td></td></tr><tr><td></td><td><code>b</code></td><td>Any real number greater than <code>a</code>, or <code>Inf</code></td><td></td></tr></tbody></table>