Package {enhancedTtest}

enhancedTtest: Enhanced T-Test with Automatic Selection and APA Formatting

Description

Provides enhanced t-test functionality with automatic assumption checking, non-parametric fallbacks, effect size calculation, and APA-formatted tables that can be exported to Word documents. Supports one-sample, two-sample, and paired t-tests with intelligent test selection. Effect size interpretations follow Cohen (1988) doi:10.4324/9780203771587 and APA formatting follows the Publication Manual of the American Psychological Association, 7th edition (2020) doi:10.1037/0000165-000.

Author(s)

Maintainer: Martin Nyamu analystnyamu79@gmail.com

Authors:

• Martin Nyamu analystnyamu79@gmail.com

Calculate Effect Size for Any Test

Description

Calculate Effect Size for Any Test

Usage

calculate_effect_size(result)

Arguments

Value

Effect size with interpretation

Complete Assumption Checking for All Test Types

Description

Complete Assumption Checking for All Test Types

Usage

check_complete_assumptions(data, response_var, group_var, test_type)

Arguments

Value

List with assumption check results

Check Homogeneity of Variance

Description

Check Homogeneity of Variance

Usage

check_homogeneity(
  data,
  response_var,
  group_var,
  method = "levene",
  alpha = 0.05
)

Arguments

Value

List with variance homogeneity results

Check Normality with Multiple Methods

Description

Check Normality with Multiple Methods

Usage

check_normality(x, method = "shapiro", alpha = 0.05)

Arguments

Value

List with normality check results

Complete T-Test Analysis with Automatic Selection

Description

Performs one-sample, two-sample, or paired t-tests with automatic non-parametric fallbacks when assumptions are violated. Handles input validation, assumption checking, effect size calculation, and produces APA-formatted output.

Usage

complete_ttest(
  data,
  formula,
  paired = FALSE,
  alternative = "two.sided",
  mu = 0,
  auto_select = TRUE,
  apa_table = TRUE,
  export_word = FALSE,
  filename = "ttest_results.docx"
)

Arguments

Value

An object of class complete_ttest (also inheriting from enhanced_ttest), which is a named list containing the following components:

raw

The raw test result object returned by t.test or wilcox.test. Contains the test statistic, degrees of freedom, p-value, confidence interval, and estimates.

method

Character string naming the test performed (e.g., "Welch's t-test", "Mann-Whitney U test").

parametric

Logical; TRUE if a parametric test was used, FALSE if a non-parametric alternative was selected.

test_type

Character string indicating the test type: "one_sample", "two_sample", or "paired".

response_var

Character string with the name of the response variable from the formula.

group_var

Character string with the name of the grouping variable from the formula, or NULL for one-sample tests.

data

The processed data frame used in the analysis, after removing missing values and converting the grouping variable to a factor (if applicable).

alternative

Character string with the alternative hypothesis used.

mu

Numeric value of the hypothesized mean (for one-sample tests).

descriptive_stats

Data frame with descriptive statistics by group (or overall for one-sample tests). Contains columns: group, N, Mean, SD, SE for parametric tests; or group, N, Median, IQR for non-parametric tests.

effect_size

A named list describing the effect size with elements:

• value: Numeric effect size value.

• name: Character string, either "Cohen's d" (parametric) or "r" (non-parametric).

• interpretation: Character string describing the magnitude (e.g., "Small", "Medium", "Large").

assumptions

A named list with results of assumption checks, including normality_passed, normality_p_value, variance_passed, variance_p_value, plus warnings and recommendations character vectors.

apa_table

A flextable object containing the publication-ready APA-formatted table, or NULL if apa_table = FALSE or table creation failed.

recommendation

Character string with a plain-language summary of the analysis, including the test method used, assumption check results, significance, and effect size interpretation.

call

The matched function call, for reproducibility.

The object has S3 methods print.complete_ttest and summary.complete_ttest for displaying results.

See Also

create_complete_apa_table for building APA tables, export_apa_to_word for Word export, format_p_value for formatting p-values.

Examples

# One-sample t-test: test if mean mpg differs from 20
result <- complete_ttest(mtcars, mpg ~ 1, mu = 20)
print(result)

# Two-sample t-test: compare Sepal.Length between two species
iris_subset <- iris[iris$Species != "virginica", ]
iris_subset$Species <- droplevels(iris_subset$Species)
result <- complete_ttest(iris_subset, Sepal.Length ~ Species)
summary(result)

# Access components
result$method          # Test name
result$raw$p.value     # p-value
result$effect_size     # Effect size with interpretation
result$apa_table       # APA-formatted flextable

Create APA Table (Alias)

Description

Alias for create_complete_apa_table.

Usage

create_apa_table(result)

Arguments

Value

A flextable object

Create APA Table for complete_ttest Object

Description

Creates a publication-ready APA-formatted table from a complete_ttest result object. Automatically selects the correct table format based on the test type (one-sample, two-sample, or paired) and whether the test was parametric or non-parametric.

Usage

create_complete_apa_table(result)

Arguments

Value

A flextable object, or NULL if descriptive statistics are not available

Examples

result <- complete_ttest(
  iris[iris$Species != "virginica", ],
  Sepal.Length ~ Species
)
create_complete_apa_table(result)

Create Complete Report in Word

Description

Generates a comprehensive Word document containing descriptive statistics, inferential tests, and interpretations for multiple outcome variables.

Usage

create_complete_report(
  data,
  formula_list,
  group_var,
  paired = FALSE,
  title = "Statistical Analysis Report",
  filename = "apa_report.docx",
  include_descriptives = TRUE,
  include_interpretations = TRUE
)

Arguments

Value

Invisibly returns the path to the created file

Examples

formulas <- list(
  Sepal.Length ~ Species,
  Sepal.Width ~ Species
)
tmp <- tempfile(fileext = ".docx")
data_subset <- iris[iris$Species != "virginica", ]
data_subset$Species <- droplevels(data_subset$Species)
create_complete_report(
  data = data_subset,
  formula_list = formulas,
  group_var = "Species",
  filename = tmp
)

Export APA Table to HTML

Description

Exports an APA-formatted flextable to an HTML file.

Usage

export_apa_to_html(
  ft,
  filename = "ttest_results.html",
  include_interpretation = TRUE,
  interpretation_text = NULL
)

Arguments

Value

Invisibly returns the path to the created file

Examples

result <- complete_ttest(
  iris[iris$Species != "virginica", ],
  Sepal.Length ~ Species
)
tmp <- tempfile(fileext = ".html")
export_apa_to_html(result$apa_table, tmp)

Export APA Table to Word

Description

Exports an APA-formatted flextable to a Word document with proper formatting. Attempts to use flextable::save_as_docx() first, with a fallback to officer for older flextable versions.

Usage

export_apa_to_word(
  apa_table,
  filename = "ttest_results.docx",
  title = "T-Test Results"
)

Arguments

Value

Invisibly returns the path to the created file

Examples

result <- complete_ttest(
  iris[iris$Species != "virginica", ],
  Sepal.Length ~ Species
)
tmp <- tempfile(fileext = ".docx")
export_apa_to_word(result$apa_table, tmp)

Format p-value for APA style

Description

Format p-value for APA style

Usage

format_p_value(p, include_stars = TRUE)

Arguments

Value

Character string with formatted p-value

Examples

format_p_value(0.0001)
format_p_value(0.03)
format_p_value(0.5)

Generate random test data

Description

Generate random test data

Usage

generate_test_data(
  n = 50,
  mean = 10,
  sd = 2,
  group1_name = "A",
  group2_name = "B",
  seed = 123
)

Arguments

Value

A data frame with columns value and group

Examples

df <- generate_test_data()

Interpret Cohen's d

Description

Interpret Cohen's d

Usage

interpret_cohens_d(d)

Arguments

Value

Character string with interpretation

Examples

interpret_cohens_d(0.3)

Interpret r (for non-parametric tests)

Description

Interpret r (for non-parametric tests)

Usage

interpret_r(r)

Arguments

Value

Character string with interpretation

Examples

interpret_r(0.4)

Print method for complete_ttest objects

Description

Formats and prints a complete_ttest object to the console in a human-readable format. The output includes the test type, method used, assumption check results, descriptive statistics, test statistics, effect size, and (if present) the APA-formatted table.

Usage

## S3 method for class 'complete_ttest'
print(x, ...)

Arguments

Value

Invisibly returns the input object x, unchanged. This function is called primarily for its side effect of printing a formatted summary of the t-test analysis to the console.

The printed output includes:

• Test information: test type ("one_sample", "two_sample", or "paired"), test method name, whether a parametric or non-parametric test was used, and the variable names.

• Assumption checks: results of normality and homogeneity of variance tests, plus any recommendations (only shown if assumption checks were performed).

• Descriptive statistics: sample size, mean, standard deviation, and standard error by group (or overall for one-sample tests). For non-parametric tests, median and interquartile range are shown instead.

• Test results: test statistic, degrees of freedom, p-value, and 95\

• Effect size: the effect size value, name (Cohen's d or r), and magnitude interpretation (e.g., "Small", "Medium", "Large").

• APA-formatted table: if x$apa_table is not NULL, the publication-ready table is printed inline.

• Summary: a plain-language summary combining the method used, assumption results, significance, and effect size.

See Also

summary.complete_ttest for a condensed summary with an APA-style interpretation, complete_ttest for the main analysis function.

Examples

result <- complete_ttest(mtcars, mpg ~ 1, mu = 20)
print(result)

Summary method for complete_ttest objects

Description

Provides a condensed summary of a complete_ttest object, including all the information shown by print.complete_ttest plus a plain-language, APA-style interpretation of the results.

Usage

## S3 method for class 'complete_ttest'
summary(object, ...)

Arguments

Value

Invisibly returns the input object object, unchanged. This function is called primarily for its side effect of printing a detailed summary of the t-test analysis to the console.

The printed output includes everything from print.complete_ttest plus:

• APA-style interpretation: a complete sentence describing the test performed, the variables compared, the statistical result (with test statistic, degrees of freedom, and p-value), and the effect size with its interpretation. This text is suitable for direct inclusion in a research report or manuscript.

See Also

print.complete_ttest, complete_ttest.

Examples

result <- complete_ttest(mtcars, mpg ~ 1, mu = 20)
summary(result)