ggeffects: values_at – R documentation

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values_at

Calculate representative values of a vector

Description

This function calculates representative values of a vector, like minimum/maximum values or lower, median and upper quartile etc., which can be used for numeric vectors to plot marginal effects at these representative values.

Usage

values_at(x, values = "meansd")

representative_values(x, values = "meansd")

Arguments

x

A numeric vector.

values

Character vector, naming a pattern for which representative values should be calculcated.

"minmax": (default) minimum and maximum values (lower and upper bounds) of the moderator are used to plot the interaction between independent variable and moderator.
"meansd": uses the mean value of the moderator as well as one standard deviation below and above mean value to plot the effect of the moderator on the independent variable.
"zeromax": is similar to the "minmax" option, however, 0 is always used as minimum value for the moderator. This may be useful for predictors that don't have an empirical zero-value, but absence of moderation should be simulated by using 0 as minimum.
"quart": calculates and uses the quartiles (lower, median and upper) of the moderator value, including minimum and maximum value.
"quart2": calculates and uses the quartiles (lower, median and upper) of the moderator value, excluding minimum and maximum value.
"all": uses all values of the moderator variable. Note that this option only applies to type = "eff", for numeric moderator values.

Value

A numeric vector of length two or three, representing the required values from x, like minimum/maximum value or mean and +/- 1 SD. If x is missing, a function, pre-programmed with n and length is returned. See examples.

Examples

data(efc)
values_at(efc$c12hour)
values_at(efc$c12hour, "quart2")

mean_sd <- values_at(values = "meansd")
mean_sd(efc$c12hour)

ggeffects

Create Tidy Data Frames of Marginal Effects for 'ggplot' from Model Outputs

v1.1.0

GPL-3

Authors

Daniel Lüdecke [aut, cre] (<https://orcid.org/0000-0002-8895-3206>), Frederik Aust [ctb] (<https://orcid.org/0000-0003-4900-788X>), Sam Crawley [ctb] (<https://orcid.org/0000-0002-7847-0411>), Mattan S. Ben-Shachar [ctb] (<https://orcid.org/0000-0002-4287-4801>)

Initial release