coin (version 1.3-1)

statistic-methods: Extraction of the Test Statistic and Linear Statistic

Description

Methods for extraction of the test statistic and linear statistic.

Usage

# S4 method for IndependenceLinearStatistic
statistic(object, type = c("test", "linear", "centered", "standardized"), …)
# S4 method for IndependenceTestStatistic
statistic(object, type = c("test", "linear", "centered", "standardized"), …)
# S4 method for IndependenceTest
statistic(object, type = c("test", "linear", "centered", "standardized"), …)

Arguments

object

an object from which the test statistic or linear statistic can be extracted.

type

a character, the type of statistic: either "test" (default) for the test statistic, "linear" for the unstandardized linear statistic "centered" for the centered linear statistic or "standardized" for the standardized linear statistic.

…

further arguments (currently ignored).

Value

The test statistic or the unstandardized, centered or standardized linear statistic extracted from object. A numeric vector or matrix.

Details

The method statistic extracts the test statistic or the, possibly multivariate, linear statistic in its unstandardized, centered or standardized form.

The test statistic (type = "test") is returned by default. The unstandardized, centered or standardized linear statistic is obtained by setting type to "linear", "centered" or "standardized" respectively.

Examples

# NOT RUN {
## Example data
dta <- data.frame(
    y = gl(4, 5),
    x = gl(5, 4)
)

## Asymptotic Cochran-Mantel-Haenszel Test
ct <- cmh_test(y ~ x, data = dta)

## Test statistic
statistic(ct)

## The unstandardized linear statistic...
statistic(ct, type = "linear")

## ...is identical to the contingency table
xtabs(~ x + y, data = dta)

## The centered linear statistic...
statistic(ct, type = "centered")

## ...is identical to
statistic(ct, type = "linear") - expectation(ct)

## The standardized linear statistic, illustrating departures from the null
## hypothesis of independence...
statistic(ct, type = "standardized")

## ...is identical to
(statistic(ct, type = "linear") - expectation(ct)) / sqrt(variance(ct))
# }