# distributions3

`distributions3`

, inspired by the eponynmous Julia package, provides a generic function interface to probability distributions. `distributions3`

has two goals:

Replace the `rnorm()`

, `pnorm()`

, etc, family of functions with S3 methods for distribution objects

Be extremely well documented and friendly for students in intro stat classes.

The main generics are:

`random()`

: Draw samples from a distribution.
`pdf()`

: Evaluate the probability density (or mass) at a point.
`cdf()`

: Evaluate the cumulative probability up to a point.
`quantile()`

: Determine the quantile for a given probability. Inverse of `cdf()`

.

## Installation

You can install `distributions3`

with:

`install.packages("distributions3")`

You can install the development version with:

```
install.packages("devtools")
devtools::install_github("alexpghayes/distributions3")
```

## Basic Usage

The basic usage of `distributions3`

looks like:

```
library(distributions3)
X <- Bernoulli(0.1)
random(X, 10)
#> [1] 0 1 0 0 0 0 0 0 0 0
pdf(X, 1)
#> [1] 0.1
cdf(X, 0)
#> [1] 0.9
quantile(X, 0.5)
#> [1] 0
```

Note that `quantile()`

**always** returns lower tail probabilities. If you arenâ€™t sure what this means, please read the last several paragraphs of `vignette("one-sample-z-confidence-interval")`

and have a gander at the plot.

## Contributing

`distributions3`

is not under active development, but is fairly stable and used by several academics for teaching intro stat courses. We are happy to review PRs contributing bug fixes. If you are interested in more actively maintaining and developing `distributions3`

, please reach out on Github!

Please note that `distributions3`

is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

For a comprehensive overview of the many packages providing various distribution related functionality see the CRAN Task View.

`distributional`

provides distribution objects as vectorized S3 objects, and is more actively developed that `distributions3`

`distr6`

builds on `distr`

, but uses R6 objects
`distr`

is quite similar to `distributions`

, but uses S4 objects and is less focused on documentation.
`fitdistrplus`

provides extensive functionality for fitting various distributions but does not treat distributions themselves as objects