This function used the MBESS function conf.limits.ncf and convert.ncf.to.omegasq to compute the point estimate and confidence interval for Omega Squared.
confIntOmegaSq(var1, var2, conf.level = 0.95)
| var1, var2 | The two variables: one should be a factor (or will be made a factor), the other should have at least interval level of measurement. If none of the variables is a factor, the function will look for the variable with the least unique values and change it into a factor. |
|---|---|
| conf.level | Level of confidence for the confidence interval. |
A confIntOmegaSq object is returned, with as elements:
The input arguments
Objects generated while computing the output
The output of the function, consisting of:
The point estimate
The confidence interval
Formula 16 in Steiger (2004) is used for the conversion in convert.ncf.to.omegasq.
Steiger, J. H. (2004). Beyond the F test: Effect size confidence intervals and tests of close fit in the analysis of variance and contrast analysis. Psychological Methods, 9(2), 164-82. https://doi.org/10.1037/1082-989X.9.2.164
confIntOmegaSq(mtcars$mpg, mtcars$cyl);#> Omega squared: 95% CI = [.51; .81], point estimate = .71