survreg {survival}  R Documentation 
Regression for a parametric survival model. These are all timetransformed location models, with the most useful case being the accelerated failure models that use a log transformation.
survreg(formula=formula(data), data=parent.frame(), weights, subset,na.action,dist="weibull", init=NULL, scale=0, control=survreg.control(),parms=NULL,model=FALSE, x=FALSE, y=TRUE, robust=FALSE, ...)
formula 
a formula expression as for other regression models.
See the documentation for lm and formula for details.

data 
optional data frame in which to interpret the variables occurring in the formula. 
weights 
Optional observation weights 
subset 
subset of the observations to be used in the fit. 
na.action 
function to be used to handle any NAs in the data. 
dist 
assumed distribution for y variable.
If the argument is a character string, then it is assumed to name an
element from survreg.distributions . These include
"weibull" , "exponential" , "gaussian" , "logistic" , "lognormal" and "loglogistic" .
Otherwise, it is assumed to be a user defined list conforming to the
format described in survreg.distributions .

parms 
a list of fixed parameters. For the tdistribution for instance this is the degrees of freedom; most of the distributions have no parameters. 
init 
optional vector of initial values for the parameters. 
scale 
optional fixed value for the scale. If set to <=0 then the scale is estimated. 
control 
a list of control values, in the format producted by survreg.control .

model 
if TRUE, the model frame is returned. 
x 
if TRUE, then the X matrix is returned. 
y 
if TRUE, then the y vector (or survival times) is returned. 
robust 
if TRUE, sandwich standard errors are computed. Defaults to TRUE when
formula contains a cluster term.

... 
other arguments which will be passed to survreg.control .

an object of class survreg
is returned.
This routine underwent significant changes from survival4 to
survival5. The survreg.old function gives a backwardscompatible
interface. In SPLUS the new function is called survReg
and
the old one survreg
.
survreg.object
, survreg.distributions
,
pspline
, frailty
, ridge
,
survreg.old
## These are all the same survreg(Surv(futime, fustat) ~ ecog.ps + rx, ovarian, dist='weibull',scale=1) survreg(Surv(futime, fustat) ~ ecog.ps + rx, ovarian, dist="exponential") survreg.old(Surv(futime, fustat) ~ ecog.ps + rx, ovarian, dist='extreme',fixed=list(scale=1),link="log")