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Compare groups for each item by calculating F-statistics and effect sizes

Source: R/effects.R
effect_metrics_items_grouped.Rd

The models are fitted using stats::lm. ANOVA of type II is computed for each fitted model using car::Anova. Eta Squared is calculated for each ANOVA result using effectsize::eta_squared.

Usage

effect_metrics_items_grouped(
  data,
  cols,
  cross,
  labels = TRUE,
  clean = TRUE,
  ...
)

Arguments

data

A tibble containing item measures.

cols

Tidyselect item variables (e.g. starts_with...).

cross

The column holding groups to compare.

labels

If TRUE (default) extracts labels from the attributes, see codebook.

clean

Prepare data by data_clean.

...

Placeholder to allow calling the method with unused parameters from effect_metrics.

Value

A volker tibble with the following statistical measures:

  • Eta-squared: Effect size indicating the proportion of variance in the dependent variable explained by the predictor.

  • Eta: Root of Eta-squared, a standardized effect size.

  • n: Number of cases the calculation is based on.

  • F: F-statistic from the linear model.

  • p: p-value for the statistical test.

  • stars: Significance stars based on p-value (*, **, ***).

Examples

library(volker)
data <- volker::chatgpt

effect_metrics(data, starts_with("cg_adoption_"), adopter)
#> 
#> 
#> |Expectations                                                | Eta-squared|  Eta|  n|     F|     p| stars|
#> |:-----------------------------------------------------------|-----------:|----:|--:|-----:|-----:|-----:|
#> |ChatGPT has clear advantages compared to similar offerings. |        0.03| 0.18| 97|  1.03| 0.719|      |
#> |Using ChatGPT brings financial benefits.                    |        0.08| 0.29| 97|  2.88| 0.011|     *|
#> |Using ChatGPT is advantageous in many tasks.                |        0.01| 0.09| 97|  0.23| 0.578|      |
#> |Compared to other systems, using ChatGPT is more fun.       |        0.03| 0.19| 97|  1.12| 0.103|      |
#> |Much can go wrong when using ChatGPT.                       |        0.00| 0.07| 97|  0.16| 0.517|      |
#> |There are legal issues with using ChatGPT.                  |        0.05| 0.21| 97|  1.47| 0.166|      |
#> |The security of user data is not guaranteed with ChatGPT.   |        0.04| 0.21| 97|  1.37| 0.146|      |
#> |Using ChatGPT could bring personal disadvantages.           |        0.04| 0.20| 97|  1.36| 0.133|      |
#> |In my environment, using ChatGPT is standard.               |        0.22| 0.47| 97|  8.96| 0.000|   ***|
#> |Almost everyone in my environment uses ChatGPT.             |        0.23| 0.48| 97|  9.05| 0.000|   ***|
#> |Not using ChatGPT is considered being an outsider.          |        0.27| 0.52| 97| 11.63| 0.000|   ***|
#> |Using ChatGPT brings me recognition from my environment.    |        0.25| 0.50| 97| 10.13| 0.000|   ***|
#> 
#> 4 missing case(s) omitted.
#>