Extract Test Statistics from a Model Fit

Extract test statistics (e.g., t-statistics, F-statistics) from a fitted model object. This is part of a family of functions for extracting statistical measures.

Usage

stats(x, ...)

# S3 method for class 'fmri_lm'
stats(x, type = c("betas", "contrasts", "F"), ...)

Arguments

x

The fitted model object

...

Additional arguments passed to methods

type

For fmri_lm fits, the parameter family whose test statistics are returned: "betas" (default) gives the t-statistics of the event coefficients, "contrasts" the t-statistics of the simple contrasts, and "F" the F-statistics of the F-contrasts. stats() never returns the estimates themselves; use coef() for those. "estimates" is a deprecated synonym of "betas" (it reads as "the estimates" but returns t-statistics) and warns; set options(fmrireg.suppress_deprecation = TRUE) to silence it.

Value

A tibble or matrix containing test statistics. For fmri_lm fits, a tibble with one row per voxel and one column per term, in the same orientation as coef().

See also

coef() for the estimates.

Other statistical_measures: coef_names(), p_values(), standard_error()

Examples

# Create example data
event_data <- data.frame(
  condition = factor(c("A", "B", "A", "B")),
  onsets = c(1, 10, 20, 30),
  run = c(1, 1, 1, 1)
)

# Create sampling frame and dataset
sframe <- sampling_frame(blocklens = 50, TR = 2)
dset <- matrix_frame(
  matrix(rnorm(50 * 2), 50, 2),
  TR = 2,
  run_length = 50,
  event_table = event_data
)

# Fit model
fit <- fmri_lm(
  onsets ~ hrf(condition),
  block = ~run,
  dataset = dset
)

# Extract test statistics
tstats <- stats(fit)