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lod <- function(object, ..., alpha = 0.05, beta = 0.05, n = 1, w = "auto")
{
UseMethod("lod")
}
lod.default <- function(object, ..., alpha = 0.05, beta = 0.05,
n = 1, w = "auto")
{
stop("lod is only implemented for univariate lm objects.")
}
lod.lm <- function(object, ..., alpha = 0.05, beta = 0.05, n = 1, w = "auto")
{
f <- function(x) {
y1 <- predict(object, data.frame(x = 0), interval="prediction",
level = 1 - alpha)
y2 <- predict(object, data.frame(x = x), interval="prediction",
level = 1 - beta)
(y2[[1,"lwr"]] - y1[[1,"upr"]])^2
}
tmp <- optimize(f,interval=c(0,max(object$model$x)))
return(tmp$minimum)
}
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