A random variable whose values are not countable is
called a **continuous random variable**. A continuous
random variable is a random variable that can assume any value contained
in one or more intervals. Because the number of values contained in any
interval is infinite, the possible number of values that a continuous
random variable can assume is also infinite (Mann 2012) .

There exist many more continuous probability distributions than we may
discuss here. However, be aware that by now a large variety of different
discrete and continuous probability distributions are implemented in R
(see here). In R probability functions are accessible
by generic prefixes, such as **r**, **d**,
**p** and **q**. The **r** is the
generic prefix for **random variable generator** such as
`runif()`

, for the uniform distribution, or
`rnorm()`

, for the normal distribution. The
**d** is the generic prefix for the **probability
density function** such as `dunif()`

and
`dnorm()`

. The **p** is the generic prefix for
the **cumulative density function** such as
`punif()`

and `pnorm()`

. The **q** is
the generic prefix for the **quantile function** such as
`qunif()`

and `qnorm()`

. Keep that in mind, while
we further explore the capacities in R.

The following functions and R-packages are used in this section (in alphabetical order):

**R-packages**

- latex2exp

**Functions**

- curve()
- dchisq()
- df()
- dunif()
- length()
- mean()
- pchisq()
- pf()
- pnorm()
- pt()
- punif()
- qchisq()
- qf()
- qnorm()
- qt()
- qunif()
- rchisq()
- read.csv()
- rt()
- runif()
- sd()
- seq()
- subset()
- sum()

**Plotting Functions**

- hist()
- qqnorm()
- qqline()

**Citation**

The E-Learning project SOGA-R was developed at the Department of Earth Sciences by Kai Hartmann, Joachim Krois and Annette Rudolph. You can reach us via mail by soga[at]zedat.fu-berlin.de.

You may use this project freely under the Creative Commons Attribution-ShareAlike 4.0 International License.

Please cite as follow: *Hartmann,
K., Krois, J., Rudolph, A. (2023): Statistics and Geodata Analysis
using R (SOGA-R). Department of Earth Sciences, Freie Universitaet Berlin.*