Gives the cumulative survival proportions at xx
from the extrinsic processes for a given set of parameter values.
SurvFn.ex.6p(xx, r, s, lambda, beta, gamma, alpha)
vector of ages
r value
s value
lambda value
beta value
gamma value
alpha value
vector cumulative survival proportions at xx
from extrinsic processes
Used within vitality.6p
for estimating model parameters based on the observed cumulative survival function.