Log-normal accelerated-failure-time model — morie_aft_generalized

\(\log T = x'\beta + \sigma W\) with W standard normal – the log-normal member of the generalized-gamma family, which is what this module provides. Like the log-logistic it gives a hazard that rises and then falls; unlike it, the survival function has no closed form and is evaluated through the normal.

Usage

morie_aft_generalized_gamma(time, event, X, ...)

Arguments

time: follow-up times, strictly positive.
event: 1 for an event, 0 for right-censored.
X: covariate matrix, one row per subject. An intercept is added.
...: passed to the fitter (max_iter, tol, add_intercept).

Value

as morie_aft_weibull.

References

Lawless, J. F. (2003). Statistical Models and Methods for Lifetime Data, 2nd ed., Sec. 5.3.

Examples

set.seed(2)
X <- matrix(rnorm(200), ncol = 2)
tt <- exp(0.5 + X %*% c(0.8, -0.4) + 0.6 * rnorm(100))
round(morie_aft_generalized_gamma(tt, rep(1, 100), X)$beta, 3)
#> [1]  0.586  0.781 -0.421