Plot Confidence or Prediction Hyperbolas around a Regression Line

Add confidence/prediction hyperbolas for \(y(x_0)\) to a plot with data or regression line.

Usage

linesHyperb.lm(object, c.prob=0.95, confidence=FALSE,
            k=if (confidence) Inf else 1,
            col=2, lty=2, do.abline=TRUE)

Arguments

object

result of lm(.).

c.prob

coverage probability in \((0,1)\).

confidence

logical; if true, do (small) confidence band, else, realistic prediction band for the mean of k observations.

k

integer or Inf; assume k future observations; k = Inf corresponds to confidence intervals (for y).

col, lty

attributes for the lines to be drawn.

do.abline

logical; if true, the regression line is drawn as well.

Note

With predict.lm(*, interval=) is available, this function linesHyperb.lm is only slightly more general for its k argument.

Author

Martin Maechler, Oct 1995

See also

predict.lm(*, interval=) optionally computes prediction or confidence intervals.

Examples

data(swiss)
      plot(Fertility ~ Education, data = swiss) # the data
(lmS <- lm(Fertility ~ Education, data = swiss))
#> 
#> Call:
#> lm(formula = Fertility ~ Education, data = swiss)
#> 
#> Coefficients:
#> (Intercept)    Education  
#>     79.6101      -0.8624  
#> 
linesHyperb.lm(lmS)
linesHyperb.lm(lmS, conf=TRUE, col="blue")