title: Gamma equivalent to standard deviations
body: <p>I have a gamma distribution fit to my data using <code>libary(fitdistrplus)</code>. I need to determine a method for defining the range of x values that can be "reasonably" expected, analogous to using standard deviations with normal distributions. </p>
  
  <p>For example, x values within two standard deviations from the mean could be considered to be the reasonable range of expected values from a normal distribution. Any suggestions for how to define a similar range of expected values based on the shape and rate parameters of a gamma distribution?</p>
  
  <p>...maybe something like identifying the two values of x that between which contains 95% of the data?</p>