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Two-Sample t-Test

Source: R/ops-timefreq.R
twoSampleTTest.Rd

Computes the two-sided independent two-sample t-test comparing two groups. By default it is Welch's t-test (unequal variances, Welch-Satterthwaite df) – matching stats::t.test and scipy.stats.ttest_ind(equal_var = FALSE); set var_equal = TRUE for Student's pooled-variance test. The standard test for a difference between two independent groups (e.g. older vs younger, patients vs controls). Reproduces both references bit-for-bit.

Usage

twoSampleTTest(x, y = NULL, var_equal = FALSE)

Arguments

x

A numeric vector (group 1), OR (when y is NULL) a list of two numeric vectors.

y

A numeric vector (group 2), or NULL if x is a two-element list.

var_equal

Logical; FALSE (default) for Welch's t-test, TRUE for Student's pooled-variance t-test.

Value

A list with statistic (the t-statistic of \(x - y\)), p_value (two-sided) and df.

See also

pairedTTest for matched samples.

Examples

set.seed(1); twoSampleTTest(rnorm(20, 1), rnorm(30))$statistic  # group 1 higher -> positive t
#> [1] 4.566756