esvis (version 0.2.0)

auc: Calculate the area under the curve

Description

This function is used within pp_plot to calculate the area under the pp curve. The area under the curve is also a useful effect-size like statistic, representing the probability that a randomly selected individual from distribution a will have a higher value than a randomly selected individual from distribution b.

Usage

auc(formula, data, ref_group = NULL, tidy = TRUE)

Arguments

formula

A formula of the type out ~ group where out is the outcome variable and group is the grouping variable. Note this variable can include any arbitrary number of groups.

data

The data frame that the data in the formula come from.

ref_group

Optional. If the name of the reference group is provided (must be character and match the grouping level exactly), only the estimates corresponding to the given reference group will be returned.

tidy

Logical. Should the data be returned in a tidy data frame? (see Wickham, 2014). If false, effect sizes returned as a vector.

Value

By default the area under the curve for all possible pairings of the grouping factor are returned as a tidy data frame. Alternatively, a vector can be returned, and/or only the auc corresponding to a specific reference group can be returned.

Examples

# NOT RUN {
free_reduced <- rnorm(800, 80, 20)
pay <- rnorm(500, 100, 10)
d <- data.frame(score = c(free_reduced, pay), 
				frl = c(rep("free_reduced", 800),  
						rep("pay", 500)))

auc(score ~ frl, d)
# Compute AUC for all pairwise comparisons
auc(reading ~ condition, star)

# Specify regular-sized classrooms as the reference group
auc(reading ~ condition, 
		star, 
		ref_group = "reg")

# Return a vector instead of a data frame
auc(reading ~ condition, 
		star, 
		ref_group = "reg", 
		tidy = FALSE)
# }