wilcoxonOR {rcompanion} | R Documentation |
Agresti's Generalized Odds Ratio for Stochastic Dominance
Description
Calculates Agresti's Generalized Odds Ratio for Stochastic Dominance (OR) with confidence intervals by bootstrap
Usage
wilcoxonOR(
formula = NULL,
data = NULL,
x = NULL,
y = NULL,
ci = FALSE,
conf = 0.95,
type = "perc",
R = 1000,
histogram = FALSE,
digits = 3,
reportIncomplete = FALSE,
verbose = FALSE,
...
)
Arguments
formula |
A formula indicating the response variable and the independent variable. e.g. y ~ group. |
data |
The data frame to use. |
x |
If no formula is given, the response variable for one group. |
y |
The response variable for the other group. |
ci |
If |
conf |
The level for the confidence interval. |
type |
The type of confidence interval to use.
Can be any of " |
R |
The number of replications to use for bootstrap. |
histogram |
If |
digits |
The number of significant digits in the output. |
reportIncomplete |
If |
verbose |
If |
... |
Additional arguments, not used. |
Details
OR is an effect size statistic appropriate in cases where a Wilcoxon-Mann-Whitney test might be used.
OR is defined as P(Ya > Yb) / P(Ya < Yb).
OR can range from 0 to infinity. An OR of 1 indicates stochastic equality between the two groups. An OR greater than 1 indicates that the first group dominates the second group. An OR less than 1 indicates that the second group dominates the first.
Be cautious with this interpretation, as R will alphabetize groups in the formula interface if the grouping variable is not already a factor.
The input should include either formula
and data
;
or x
, and y
. If there are more than two groups,
only the first two groups are used.
Currently, the function makes no provisions for NA
values in the data. It is recommended that NA
s be removed
beforehand.
With a small sample size, or with an OR near its extremes, the confidence intervals determined by this method may not be reliable, or the procedure may fail.
Value
A single statistic, OR. Or a small data frame consisting of OR, and the lower and upper confidence limits.
Note
The parsing of the formula is simplistic. The first variable on the left side is used as the measurement variable. The first variable on the right side is used for the grouping variable.
Author(s)
Salvatore Mangiafico, mangiafico@njaes.rutgers.edu
References
Grissom, R.J. and J.J. Kim. 2012. Effect Sizes for Research. 2nd ed. Routledge, New York.
https://rcompanion.org/handbook/F_04.html
See Also
Examples
data(Catbus)
wilcoxonOR(Steps ~ Gender, data=Catbus, verbose=TRUE)