rcompanion (version 2.4.30)

groupwiseMedian: Groupwise medians and confidence intervals

Description

Calculates medians and confidence intervals for groups.

Usage

groupwiseMedian(
  formula = NULL,
  data = NULL,
  var = NULL,
  group = NULL,
  conf = 0.95,
  R = 5000,
  boot = FALSE,
  pseudo = FALSE,
  basic = FALSE,
  normal = FALSE,
  percentile = FALSE,
  bca = TRUE,
  wilcox = FALSE,
  exact = FALSE,
  digits = 3,
  ...
)

Value

A data frame of requested statistics by group.

Arguments

formula

A formula indicating the measurement variable and the grouping variables. e.g. y ~ x1 + x2.

data

The data frame to use.

var

The measurement variable to use. The name is in double quotes.

group

The grouping variable to use. The name is in double quotes. Multiple names are listed as a vector. (See example.)

conf

The confidence interval to use.

R

The number of bootstrap replicates to use for bootstrapped statistics.

boot

If TRUE, includes the mean of the bootstrapped medians. This can be used as an estimate of the median for the group.

pseudo

If TRUE, includes the pseudo median from wilcox.test.

basic

If TRUE, includes the basic confidence intervals for the group means by bootstrap. See boot::boot.ci.

normal

If TRUE, includes the normal confidence intervals for the group means by bootstrap. See boot::boot.ci.

percentile

If TRUE, includes the percentile confidence intervals for the group means by bootstrap. See boot::boot.ci.

bca

If TRUE, includes the BCa confidence intervals for the group means by bootstrap. See boot::boot.ci.

wilcox

If TRUE, includes the wilcox confidence intervals from stats::wilcox.test.

exact

If TRUE, includes the "exact" confidence intervals from DescTools::MedianCI.

digits

The number of significant figures to use in output.

...

Other arguments passed to the boot function.

Author

Salvatore Mangiafico,

Details

The input should include either formula and data; or data, var, and group. (See examples).

With some options, the function may not handle missing values well. This seems to happen particularly with bca = TRUE.

References

http://rcompanion.org/handbook/E_04.html

See Also

groupwiseMean, groupwiseHuber, groupwiseGeometric

Examples

### Example with formula notation
data(Catbus)
groupwiseMedian(Steps ~ Teacher + Gender,
                data        = Catbus,
                bca         = FALSE,
                percentile  = TRUE,
                R           = 1000)
                
### Example with variable notation
data(Catbus)
groupwiseMedian(data         = Catbus,
                var         = "Steps",
                group       = c("Teacher", "Gender"),
                bca         = FALSE,
                percentile  = TRUE,
                R           = 1000)