Prediction Method for betareg Objects

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Description

Extract various types of predictions from beta regression models: either on the scale of responses in (0, 1) or the scale of the linear predictor.

Usage

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## S3 method for class 'betareg'
predict(object, newdata = NULL,
  type = c("response", "link", "precision", "variance", "quantile"),
  na.action = na.pass, at = 0.5, ...)

Arguments

object

fitted model object of class "betareg".

newdata

optionally, a data frame in which to look for variables with which to predict. If omitted, the original observations are used.

type

character indicating type of predictions: fitted means of response ("response"), corresponding linear predictor ("link"), fitted precision parameter phi ("precision"), fitted variances of response ("variance"), or fitted quantile(s) of the response distribution ("quantile").

na.action

function determining what should be done with missing values in newdata. The default is to predict NA.

at

numeric vector indicating the level(s) at which quantiles should be predicted (only if type = "quantile"), defaulting to the median at = 0.5.

...

currently not used.

Examples

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options(digits = 4)

data("GasolineYield", package = "betareg")

gy2 <- betareg(yield ~ batch + temp | temp, data = GasolineYield)

cbind(
  predict(gy2, type = "response"),
  predict(gy2, type = "link"),
  predict(gy2, type = "precision"),
  predict(gy2, type = "variance"),
  predict(gy2, type = "quantile", at = c(0.25, 0.5, 0.75))
)