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predint (version 2.2.1)

bisection: Bisection algorithm for bootstrap calibration of prediction intervals

Description

This helper function returns a bootstrap calibrated coefficient for the calculation of prediction intervals (and limits).

Usage

bisection(
  y_star_hat,
  pred_se,
  y_star,
  alternative,
  quant_min,
  quant_max,
  n_bisec,
  tol,
  alpha,
  traceplot = TRUE
)

Value

This function returns \(q^{calib}\) in the equation above.

Arguments

y_star_hat

a list of length \(B\) that contains the expected future observations. Each entry in this list has to be a numeric vector of length \(M\).

pred_se

a list of length \(B\) that contains the standard errors of the prediction. Each entry in this list has to be a numeric vector of length \(M\).

y_star

a list of length \(B\) that contains the future observations. Each entry in this list has to be a numeric vector of length \(M\).

alternative

either "both", "upper" or "lower". alternative specifies if a prediction interval or an upper or a lower prediction limit should be computed

quant_min

lower start value for bisection

quant_max

upper start value for bisection

n_bisec

maximal number of bisection steps

tol

tolerance for the coverage probability in the bisection

alpha

defines the level of confidence (\(1-\alpha\))

traceplot

if TRUE: Plot for visualization of the bisection process

Details

This function is an implementation of the bisection algorithm of Menssen and Schaarschmidt 2022. It returns a calibrated coefficient \(q^{calib}\) for the calculation of pointwise and simultaneous prediction intervals $$[l,u] = \hat{y}^*_m \pm q^{calib} \hat{se}(Y_m - y^*_m),$$ lower prediction limits $$l = \hat{y}^*_m - q^{calib} \hat{se}(Y_m - y^*_m)$$ or upper prediction limits $$u = \hat{y}^*_m + q^{calib} \hat{se}(Y_m - y^*_m)$$ that cover all of \(m=1, ... , M\) future observations.

In this notation, \(\hat{y}^*_m\) are the expected future observations for each of the \(m\) future clusters, \(q^{calib}\) is the calibrated coefficient and \(\hat{se}(Y_m - y^*_m)\) are the standard errors of the prediction.

References

Menssen and Schaarschmidt (2022): Prediction intervals for all of M future observations based on linear random effects models. Statistica Neerlandica.
tools:::Rd_expr_doi("10.1111/stan.12260")