isurvfit.object: IDP Survival Curve Object
In IDPSurvival: Imprecise Dirichlet Process for Survival Analysis

This class of objects is returned by the isurvfit class of functions to represent a IDP survival curve.

Objects of this class have methods for the functions print, plot.

`n`	total number of subjects in each curve.
`time`	the time points at which the curve has a step.
`n.risk`	the number of subjects at risk at t.
`n.event`	the number of events that occur at time t.
`n.censor`	the number of subjects who exit the risk set, without an event, at time t. (This number can be computed from the successive values of the number at risk).
`survUP`	the estimate of upper expectation of the survival probability at time t+0.
`survLOW`	the estimate of lower expectation of the survival probability at time t+0.
`survLOW0`	the estimate of lower expectation of the survival probability at time t=0. The upper expectation is always 1.
`std.up`	the standard deviation of the upper distribution of the survival probability.
`std.low`	the standard deviation of the lower distribution of the survival probability.
`upper`	upper confidence limit for the survival curve.
`lower`	lower confidence limit for the survival curve.
`lower0`	lower confidence limit for the survival curve at t=0. The upper is always 1.
`conf.type`	the approximation used to compute the confidence limits.
`conf.int`	the level of the confidence limits, e.g. 90 or 95%.
`strata`	number of elements of the `time` vector corresponding to each curve. The names of the elements are labels for the curves.
`call`	an image of the call that produced the object.