statsExpressions (version 0.3.1)

bf_ttest: Bayes Factor for t-test

Description

Bayes Factor for t-test

Usage

bf_ttest(
  data,
  x,
  y = NULL,
  test.value = 0,
  paired = FALSE,
  bf.prior = 0.707,
  caption = NULL,
  output = "null",
  k = 2,
  ...
)
bf_one_sample_ttest(
  data,
  x,
  y = NULL,
  test.value = 0,
  paired = FALSE,
  bf.prior = 0.707,
  caption = NULL,
  output = "null",
  k = 2,
  ...
)
bf_two_sample_ttest(
  data,
  x,
  y = NULL,
  test.value = 0,
  paired = FALSE,
  bf.prior = 0.707,
  caption = NULL,
  output = "null",
  k = 2,
  ...
)

Arguments

data

A dataframe (or a tibble) from which variables specified are to be taken. A matrix or tables will not be accepted.

x

Either the grouping variable from the dataframe data if it's a two-sample t-test or a numeric variable if it's a one-sample t-test.

y

The response (a.k.a. outcome or dependent) variable from the dataframe data.

test.value

A number specifying the value of the null hypothesis (Default: 0).

paired

Logical that decides whether the experimental design is repeated measures/within-subjects or between-subjects. The default is FALSE.

bf.prior

A numeric value between 0.5 and 2 (default 0.707), the prior width to use in calculating Bayes Factors.

caption

Text to display as caption (will be displayed on top of the Bayes Factor caption/message).

output

Can either be "null" (or "caption" or "H0" or "h0"), which will return expression with evidence in favor of the null hypothesis, or "alternative" (or "title" or "H1" or "h1"), which will return expression with evidence in favor of the alternative hypothesis, or "results", which will return a dataframe with results all the details).

k

Number of digits after decimal point (should be an integer) (Default: k = 2).

...

Additional arguments (currently ignored).

Details

If y is NULL, a one-sample t-test will be carried out, otherwise a two-sample t-test will be carried out.

See Also

bf_contingency_tab, bf_corr_test, bf_oneway_anova

Examples

# NOT RUN {
# ------------------- two-samples tests -----------------------------------

# for reproducibility
set.seed(123)
library(statsExpressions)

# to get caption (default)
bf_ttest(
  data = mtcars,
  x = am,
  y = wt,
  paired = FALSE,
  bf.prior = 0.880
)

# to see results
bf_ttest(
  data = mtcars,
  x = am,
  y = wt,
  paired = FALSE,
  output = "results"
)

# for paired sample test
bf_ttest(
  data = dplyr::filter(
    statsExpressions::intent_morality,
    condition %in% c("accidental", "attempted"),
    harm == "Poisoning"
  ),
  x = condition,
  y = rating,
  paired = TRUE,
  output = "results"
)

# ------------------- one-samples test -----------------------------------

# to get caption (default)
bf_ttest(
  data = iris,
  x = Sepal.Length,
  test.value = 5.85,
  bf.prior = 0.8,
  output = "caption", k = 2
)

# to get results dataframe
bf_ttest(
  data = iris,
  x = Sepal.Length,
  test.value = 5.85,
  bf.prior = 0.8,
  output = "results"
)
# }