# IQR

0th

Percentile

##### The Interquartile Range

computes interquartile range of the x values.

Keywords
robust, distribution, univar
##### Usage
IQR(x, na.rm = FALSE, type = 7)
##### Arguments
x
a numeric vector.
na.rm
logical. Should missing values be removed?
type
an integer selecting one of the many quantile algorithms, see quantile.
##### Details

Note that this function computes the quartiles using the quantile function rather than following Tukey's recommendations, i.e., IQR(x) = quantile(x, 3/4) - quantile(x, 1/4).

For normally $N(m,1)$ distributed $X$, the expected value of IQR(X) is 2*qnorm(3/4) = 1.3490, i.e., for a normal-consistent estimate of the standard deviation, use IQR(x) / 1.349.

##### References

fivenum, mad which is more robust, range, quantile.
library(stats) IQR(rivers)