# area_under_curve: Area under the Curve (AUC) In easystats/bayestestR: Understand and Describe Bayesian Models and Posterior Distributions

 area_under_curve R Documentation

## Area under the Curve (AUC)

### Description

Based on the DescTools `AUC` function. It can calculate the area under the curve with a naive algorithm or a more elaborated spline approach. The curve must be given by vectors of xy-coordinates. This function can handle unsorted x values (by sorting x) and ties for the x values (by ignoring duplicates).

### Usage

``````area_under_curve(x, y, method = c("trapezoid", "step", "spline"), ...)

auc(x, y, method = c("trapezoid", "step", "spline"), ...)
``````

### Arguments

 `x` Vector of x values. `y` Vector of y values. `method` Method to compute the Area Under the Curve (AUC). Can be `"trapezoid"` (default), `"step"` or `"spline"`. If "trapezoid", the curve is formed by connecting all points by a direct line (composite trapezoid rule). If "step" is chosen then a stepwise connection of two points is used. For calculating the area under a spline interpolation the splinefun function is used in combination with integrate. `...` Arguments passed to or from other methods.

DescTools

### Examples

``````library(bayestestR)
posterior <- distribution_normal(1000)

dens <- estimate_density(posterior)
dens <- dens[dens\$x > 0, ]
x <- dens\$x
y <- dens\$y

area_under_curve(x, y, method = "trapezoid")
area_under_curve(x, y, method = "step")
area_under_curve(x, y, method = "spline")
``````

easystats/bayestestR documentation built on Sept. 15, 2024, 5:38 a.m.