# sd

0th

Percentile

##### Standard Deviation

This function computes the standard deviation of the values in x. If na.rm is TRUE then missing values are removed before computation proceeds.

Keywords
univar
##### Usage
sd(x, na.rm = FALSE)
##### Arguments
x
a numeric vector or an R object which is coercible to one by as.vector(x, "numeric").
na.rm
logical. Should missing values be removed?
##### Details

Like var this uses denominator $n - 1$.

The standard deviation of a zero-length vector (after removal of NAs if na.rm = TRUE) is not defined and gives an error. The standard deviation of a length-one vector is NA.

var for its square, and mad, the most robust alternative.

• sd
##### Examples
library(stats) sd(1:2) ^ 2 
Documentation reproduced from package stats, version 3.1.1, License: Part of R 3.1.1

### Community examples

richie@datacamp.com at Jan 17, 2017 stats v3.3.1

The standard deviation of random numbers should be close to (but not exactly) what you ask for. {r} x <- rnorm(1000, sd = 5) sd(x)  If there are any missing values, the standard deviation is also missing. {r} sd(c(1, 2, NA))  You can exclude missing values by setting na.rm = TRUE. {r} sd(c(1, 2, NA), na.rm = TRUE)  If x has length 1 or 0, the result is NA. {r} sd(1) sd(numeric())