The post Gamma distribution in R appeared first on Data Science Tutorials

What do you have to lose?. Check out Data Science tutorials here Data Science Tutorials.

Gamma distribution in R, This guide demonstrates how to use R to fit a gamma distribution to a dataset.

Gamma Distribution Fitting in R

Let’s say you have a dataset z that was produced using the following method:

Create 30 random values that are distributed according to a gamma distribution with shape parameters of 4 and 9 along with some gaussian noise.

Gama <- rgamma(30, 4, 9) + rnorm(30, 0, .03)

Now we can view the first 6 values

head(Gama)
[1] 0.1362240 0.5979568 0.4930604 0.2808689 0.4361617

With the help of the fitdistrplus package in R, we can examine how well a gamma distribution fits this dataset Gama.

if not already installed, install the ‘fitdistrplus’ package.

install.packages('fitdistrplus')

Yes, now we can load the package

library(fitdistrplus)

To fit a distribution using this package, the following general syntax should be used:

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

In this instance, we’ll use the gamma distribution and maximum likelihood estimation approach to suit the dataset z that we created earlier:

Using mle, we fitted our dataset to a gamma distribution.

fit <- fitdist(Gama, distr = "gamma", method = "mle")

Let’s view the summary of the fit

summary(fit)

Fitting of the distribution ‘ gamma ‘ by maximum likelihood

Parameters :
      estimate Std. Error
shape 3.551416   0.647940
rate  7.019582   1.375659
Loglikelihood:  -0.1783264   AIC:  4.356653   BIC:  8.371319
Correlation matrix:
          shape      rate
shape 1.0000000 0.9309661
rate  0.9309661 1.0000000

The following syntax can then be used to create several charts that demonstrate how well the gamma distribution fits the dataset.

par(mar=c(1, 1, 1, 1))
plot(fit)

Further Resources:-
The following tutorials provide guidance on using R to manipulate various probability distributions:

The Multinomial Distribution in R – Data Science Tutorials

The Uniform Distribution in R – Data Science Tutorials

Test for Normal Distribution in R-Quick Guide – Data Science Tutorials

The post Gamma distribution in R appeared first on Data Science Tutorials

Learn how to expert in the Data Science field with Data Science Tutorials.