MedianCI: Confidence Interval for the Median

In DescTools: Tools for Descriptive Statistics

Confidence Interval for the Median

Description

Calculate the confidence interval for the median.

Usage

MedianCI(
  x,
  conf.level = 0.95,
  sides = c("two.sided", "left", "right"),
  method = c("exact", "boot"),
  na.rm = FALSE,
  ...
)

Arguments

x	a (non-empty) numeric vector of data values.
conf.level	confidence level of the interval
sides	a character string specifying the side of the confidence interval, must be one of "two.sided" (default), "left" or "right". You can specify just the initial letter. "left" would be analogue to a hypothesis of "greater" in a t.test.
method	defining the type of interval that should be calculated (one out of "exact", "boot"). Default is "exact". See Details.
na.rm	logical. Should missing values be removed? Defaults to FALSE.
...	the dots are passed on to boot.ci. In particular, the type of bootstrap confidence interval can be defined via this. The defaults are R=999 and type="perc".

Details

The "exact" method is the way SAS is said to calculate the confidence interval. This is also implemented in SignTest. The boot confidence interval type is calculated by means of boot.ci with default type "perc".
Use sapply, resp.apply, to get the confidence intervals from a data.frame or from a matrix.

Value

a numeric vector with 3 elements:

median	median
lwr.ci	lower bound of the confidence interval
upr.ci	upper bound of the confidence interval

Author(s)

Andri Signorell [e-mail]

See Also

wilcox.test, MeanCI, median, HodgesLehmann

Examples

MedianCI(d.pizza$price, na.rm=TRUE)
MedianCI(d.pizza$price, conf.level=0.99, na.rm=TRUE)

t(round(sapply(d.pizza[,c("delivery_min","temperature","price")], MedianCI, na.rm=TRUE), 3))

MedianCI(d.pizza$price, na.rm=TRUE, method="exact")
MedianCI(d.pizza$price, na.rm=TRUE, method="boot")


x <- runif(100)

set.seed(448)
MedianCI(x, method="boot")

# ... the same as
set.seed(448)
MedianCI(x, method="boot", type="bca")

MedianCI(x, method="boot", type="basic")
MedianCI(x, method="boot", type="perc")
MedianCI(x, method="boot", type="norm", R=499)
# not supported:
MedianCI(x, method="boot", type="stud")

MedianCI(x, method="boot", sides="right")

DescTools documentation built on April 4, 2025, 1:55 a.m.