intercept function

Intercept estimates from segmented relationships

Intercept estimates from segmented relationships

Computes the intercepts of each `segmented' relationship in the fitted model.

intercept(ogg, parm, rev.sgn = FALSE, var.diff=FALSE, .vcov=NULL, .coef=NULL, digits = max(4, getOption("digits") - 2),...)

Arguments

  • ogg: an object of class "segmented", returned by any segmented method.

  • parm: the segmented variable whose intercepts have to be computed. If missing all the segmented variables in the model are considered.

  • rev.sgn: vector of logicals. The length should be equal to the length of parm, but it is recycled otherwise. When TRUE it is assumed that the current parm is `minus' the actual segmented variable, therefore the order is reversed before printing. This is useful when a null-constraint has been set on the last slope.

  • var.diff: Currently ignored as only point estimates are computed.

  • .vcov: The full covariance matrix of estimates. If unspecified (i.e. NULL), the covariance matrix is computed internally by vcov(ogg).

  • .coef: The regression parameter estimates. If unspecified (i.e. NULL), it is computed internally by coef(ogg).

  • digits: controls number of digits in the returned output.

  • ...: Further arguments to be passed on to vcov.segmented, such as var.diff and is. See Details in vcov.segmented.

Details

A broken-line relationship means that a regression equation exists in the intervals $min(x)$ to $psi1$', psi1psi1 to psi2psi2', and so on. intercept computes point estimates of the intercepts of the different regression equations for each segmented relationship in the fitted model.

Returns

intercept returns a list of one-column matrices. Each matrix represents a segmented relationship.

Author(s)

Vito M. R. Muggeo, vito.muggeo@unipa.it

See Also

See also slope to compute the slopes of the different regression equations for each segmented relationship in the fitted model.

Examples

## see ?slope ## Not run: intercept(out.seg) ## End(Not run)
  • Maintainer: Vito M. R. Muggeo
  • License: GPL
  • Last published: 2024-10-25

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