crawford_dissociation.test: Crawford-Howell (1998) modified t-test for testing difference...

In psycho: Efficient and Publishing-Oriented Workflow for Psychological Science

Description

Assessing dissociation between processes is a fundamental part of clinical neuropsychology. However, while the detection of suspected impairments is a fundamental feature of single-case studies, evidence of an impairment on a given task usually becomes of theoretical interest only if it is observed in the context of less impaired or normal performance on other tasks. Crawford and Garthwaite (2012) demonstrate that the Crawford-Howell (1998) t-test for dissociation is a better approach (in terms of controlling Type I error rate) than other commonly-used alternatives. .

Usage

crawford_dissociation.test(
  case_X,
  case_Y,
  controls_X,
  controls_Y,
  verbose = TRUE
)

Arguments

case_X	Single value (patient's score on test X).
case_Y	Single value (patient's score on test Y).
controls_X	Vector of values (control's scores of X).
controls_Y	Vector of values (control's scores of Y).
verbose	True or False. Prints the interpretation text.

Value

Returns a data frame containing the t-value, degrees of freedom, and p-value. If significant, the dissociation between test X and test Y is significant.

Author(s)

Dominique Makowski

Examples

library(psycho)

case_X <- 142
case_Y <- 7
controls_X <- c(100, 125, 89, 105, 109, 99)
controls_Y <- c(7, 8, 9, 6, 7, 10)

crawford_dissociation.test(case_X, case_Y, controls_X, controls_Y)

Example output

Note: Many functions of the 'psycho' package have been (improved and) moved to other packages of the new 'easystats' collection (https://github.com/easystats). If you don't find where a function is gone, please open an issue at: https://github.com/easystats/easystats/issues
The Crawford-Howell (1998) t-test suggests no dissociation between test X and test Y (t(5) = 2.10, p p = 0.090). The patient's score on test X is not significantly altered compared to its score on test Y.

         t df          p
1 2.097994  5 0.08998205

psycho documentation built on Jan. 19, 2021, 9:07 a.m.