*16*

This tutorial explains how to fit a **gamma distribution** to a dataset in R.

**Fitting a Gamma Distribution in R**

Suppose you have a dataset *z *that was generated using the approach below:

#generate 50 random values that follow a gamma distribution with shape parameter = 3 #and shape parameter = 10 combined with some gaussian noise z #view first 6 values head(z) [1] 0.07730 0.02495 0.12788 0.15011 0.08839 0.09941

To see how well a gamma distribution fits this dataset *z*, we can use the **fitdistrplus** package in R:

#install 'fitdistrplus' package if not already installed install.packages('fitdistrplus') #load package library(fitdistrplus)

The general syntax to use to fit a distribution using this package is:

**fitdist(dataset, distr = “your distribution choice”, method = “your method of fitting the data”)**

In this case, we will fit the dataset *z *that we generated earlier using the gamma distribution and maximum likelihood estimation approach to fitting the data:

#fit our dataset to a gamma distribution using mle fit #view the summary of the fit summary(fit)

This produces the following output:

Next, we can produce some plots that show how well the gamma distribution fits the dataset using the following syntax:

#produce plots plot(fit)

This produces the following plots:

Here is the complete code we used to fit a gamma distribution to a dataset in R:

#install 'fitdistrplus' package if not already installed install.packages('fitdistrplus') #load package library(fitdistrplus) #generate 50 random values that follow a gamma distribution with shape parameter = 3 #and shape parameter = 10 combined with some gaussian noise z #fit our dataset to a gamma distribution using mle fit #view the summary of the fit summary(fit) #produce plots to visualize the fit plot(fit)