Uniform {stats}R Documentation

The Uniform Distribution

Description

Density, distribution function, quantile function and random generation for the uniform distribution on the interval from min to max.

Usage

dunif(x, min = 0, max = 1, log = FALSE)
punif(q, min = 0, max = 1, lower.tail = TRUE, log.p = FALSE)
qunif(p, min = 0, max = 1, lower.tail = TRUE, log.p = FALSE)
runif(n, min = 0, max = 1)

Arguments

x, q

vector of quantiles.

p

vector of probabilities.

n

number of observations. If length(n) > 1, the length is taken to be the number required.

min, max

lower and upper limits of the distribution. Must be finite.

log, log.p

logical; if TRUE, probabilities/densities are given as logarithms.

lower.tail

logical; if TRUE (default), probabilities are P[X \le x], otherwise, P[X > x].

Details

If min or max are not specified they assume the default values of 0 and 1 respectively.

The uniform distribution has density

f(x) = \frac{1}{max-min}

for min \le x \le max.

For the case of u := min == max, the limit case of X \equiv u is assumed, although there is no density in that case and dunif will return NaN (the error condition).

runif will not generate either of the extreme values unless max = min or max-min is small compared to min, and in particular not for the default arguments.

Value

dunif gives the density, punif is the cumulative distribution function, and qunif is the quantile function of the uniform distribution. runif generates random deviates.

The length of the result is determined by n for runif, and is the maximum of the lengths of the numerical arguments for the other functions.

The numerical arguments other than n are recycled to the length of the result. Only the first elements of the logical arguments are used.

Note

The characteristics of output from pseudo-random number generators (such as precision and periodicity) vary widely. See .Random.seed for more information on R's random number generation algorithms.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

RNG about random number generation in R.

Distributions for other standard distributions.

Examples

u <- runif(20)

## The following relations always hold :
punif(u) == u
dunif(u) == 1

var(runif(10000))  #- ~ = 1/12 = .08333

[Package stats version 4.6.0 Index]