Function to run t-test on multiple variables across multiple grouping variables.

grouped_ttest(
  data,
  dep.vars,
  indep.vars,
  grouping.vars,
  paired = FALSE,
  var.equal = FALSE
)

Arguments

data	Dataframe from which variables are to be taken.
dep.vars	List dependent variables for a t-test (`y` in `y ~ x`).
indep.vars	List independent variables for a t-test (`x` in `y ~ x`).
grouping.vars	List of grouping variables.
paired	A logical indicating whether you want a paired t-test (Default: `paired = FALSE`; independent t-test, i.e.).
var.equal	A logical variable indicating whether to treat the two variances as being equal. If `TRUE`, then the pooled variance is used to estimate the variance otherwise the Welch (or Satterthwaite) approximation to the degrees of freedom is used (Default: `var.equal = FALSE`; Welch's t-test, i.e.).

Value

A tibble dataframe with tidy results from t-test analyses.

Examples

# for reproducibility
set.seed(123)

groupedstats::grouped_ttest(
  data = dplyr::filter(.data = ggplot2::diamonds, color == "E" | color == "J"),
  dep.vars = c(carat, price, depth),
  indep.vars = color,
  grouping.vars = clarity,
  paired = FALSE,
  var.equal = FALSE
)
#> # A tibble: 24 x 10
#>    clarity formula method t.test estimate conf.low conf.high parameter   p.value
#>    <ord>   <chr>   <chr>   <dbl>    <dbl>    <dbl>     <dbl>     <dbl>     <dbl>
#>  1 SI2     carat … Welch… -18.0  -5.03e-1 -5.58e-1  -4.48e-1     634.  9.24e- 59
#>  2 SI1     carat … Welch… -22.1  -4.62e-1 -5.03e-1  -4.20e-1     948.  2.47e- 87
#>  3 VS1     carat … Welch… -16.8  -4.44e-1 -4.96e-1  -3.92e-1     663.  2.91e- 53
#>  4 VVS2    carat … Welch… -12.0  -5.53e-1 -6.44e-1  -4.61e-1     140.  3.81e- 23
#>  5 VS2     carat … Welch… -24.6  -5.42e-1 -5.86e-1  -4.99e-1     856.  1.51e-101
#>  6 I1      carat … Welch…  -4.48 -6.44e-1 -9.32e-1  -3.57e-1      60.6 3.34e-  5
#>  7 VVS1    carat … Welch…  -6.53 -4.17e-1 -5.45e-1  -2.90e-1      76.1 6.68e-  9
#>  8 IF      carat … Welch…  -2.38 -1.98e-1 -3.64e-1  -3.18e-2      60.1 2.03e-  2
#>  9 SI2     price … Welch… -10.6  -2.35e+3 -2.78e+3  -1.91e+3     676.  2.02e- 24
#> 10 SI1     price … Welch… -12.6  -2.02e+3 -2.34e+3  -1.71e+3    1031.  5.75e- 34
#> # … with 14 more rows, and 1 more variable: significance <chr>