Mean and restricted mean survival functions

Mean and restricted mean survival time functions for distributions which are built into flexsurv.

Usage

mean_exp(rate = 1)

rmst_exp(t, rate = 1, start = 0)

mean_gamma(shape, rate = 1)

rmst_gamma(t, shape, rate = 1, start = 0)

rmst_genf(t, mu, sigma, Q, P, start = 0)

mean_genf(mu, sigma, Q, P)

rmst_genf.orig(t, mu, sigma, s1, s2, start = 0)

mean_genf.orig(mu, sigma, s1, s2)

rmst_gengamma(t, mu = 0, sigma = 1, Q, start = 0)

mean_gengamma(mu = 0, sigma = 1, Q)

rmst_gengamma.orig(t, shape, scale = 1, k, start = 0)

mean_gengamma.orig(shape, scale = 1, k)

rmst_gompertz(t, shape, rate = 1, start = 0)

mean_gompertz(shape, rate = 1)

mean_llogis(shape = 1, scale = 1)

rmst_llogis(t, shape = 1, scale = 1, start = 0)

mean_lnorm(meanlog = 0, sdlog = 1)

rmst_lnorm(t, meanlog = 0, sdlog = 1, start = 0)

mean_weibull(shape, scale = 1)

rmst_weibull(t, shape, scale = 1, start = 0)

rmst_weibullPH(t, shape, scale = 1, start = 0)

mean_weibullPH(shape, scale = 1)

Arguments

rate

Rate parameter (exponential and gamma)

t

Vector of times to which restricted mean survival time is evaluated

start

Optional left-truncation time or times. The returned restricted mean survival will be conditioned on survival up to this time.

shape

Shape parameter (Weibull, gamma, log-logistic, generalized gamma [orig], generalized F [orig])

mu

Mean on the log scale (generalized gamma, generalized F)

sigma

Standard deviation on the log scale (generalized gamma, generalized F)

Q

Vector of first shape parameters (generalized gamma, generalized F)

P

Vector of second shape parameters (generalized F)

s1

Vector of first F shape parameters (generalized F [orig])

s2

vector of second F shape parameters (generalized F [orig])

scale

Scale parameter (Weibull, log-logistic, generalized gamma [orig], generalized F [orig])

k

vector of shape parameters (generalized gamma [orig]).

meanlog

Mean on the log scale (log normal)

sdlog

Standard deviation on the log scale (log normal)

Value

mean survival (functions beginning 'mean') or restricted mean survival (functions beginning 'rmst_').

Details

For the exponential, Weibull, log-logistic, lognormal, and gamma, mean survival is provided analytically. Restricted mean survival for the exponential distribution is also provided analytically. Mean and restricted means for other distributions are calculated via numeric integration.

See also

dexp,dweibull,dgamma,dlnorm,dgompertz,dgengamma,dgenf

Author

Christopher Jackson <chris.jackson@mrc-bsu.cam.ac.uk>