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Modified t test

Source: R/spatial_t_test.R
spatial_t_test.Rd

Performs a modified t-test to assess the correlation between variables while accounting for spatial autocorrelation. This implementation wraps SpatialPack::modified.ttest.

Usage

spatial_t_test(data, variables)

Arguments

data

An sf object containing geometry and variables, or a matrix/data.frame with two columns representing spatial coordinates (e.g., X and Y).

variables

A character vector with the names of the variables to be tested. If data is not an sf object, this should be a matrix or data.frame of variables to test.

Value

A data.frame with the following columns:

Var1

Name of the first variable

Var2

Name of the second variable

corr

Estimated correlation coefficient

p.value

P-value adjusted for spatial autocorrelation

Details

The function computes pairwise correlations between the specified variables and adjusts the significance test to account for spatial dependence using coordinates. If data is an sf object, coordinates are extracted automatically. Otherwise, coordinates must be provided as an object with two columns.

See also

modified.ttest

Examples

if (requireNamespace("SpatialPack", quietly = TRUE)) {
  library(sf)
  data(wheat, package = 'paar')

  # Transform the data.frame into a sf object
  wheat_sf <- st_as_sf(wheat, coords = c('x', 'y'), crs = 32720)

  # Run spatial t test
  t_test_results <-
    spatial_t_test(
      wheat_sf,
      variables = c('CE30', 'CE90')
    )

  # Print the t_test_results
  t_test_results
}
#>   Var1 Var2     corr     p.value
#> 1 CE30 CE90 0.567425 0.002973324