t_test {miceafter}

Calculates the one, two and paired sample t-test

Description

t_test Calculates the one, two and paired sample t-test.

Usage

t_test(y, x, formula, data, paired = FALSE, var_equal = TRUE)

Arguments

y

numeric response variable.

x

categorical variable with 2 groups.

formula

A formula object to specify the model as normally used by glm.

data

An objects of class milist, created by df2milist, list2milist or mids2milist.

paired

a logical indicating whether you want a paired t-test (TRUE) or not (FALSE, default).

var_equal

a logical, if TRUE equal variances are assumed, if FALSE (default) equal variances are not assumed and Welch correction is applied for the number of degrees of freedom. See detail.

Details

For all t-tests the dataset must be in long format (i.e. group data under each other). For the paired t-test x and y must have the same length. When variances between groups are unequal, the Welch df correction formula is used and eventually averaged across multiply imputed datasets in the pool_t_test function.

Value

An object containing the following objects are extracted:

• mdiff the mean difference.

• se the standard error.

• dfcom the complete data degrees of freedom.

Author(s)

Martijn Heymans, 2022

See Also

with.milist, pool_t_test

Examples

imp_dat <- df2milist(lbpmilr, impvar="Impnr")
ra <- with(imp_dat, expr=t_test(Pain ~ Gender))