Part of the set of internal functions for estimating bootstrapped confidence intervals
for continuous outcome and two treatment groups when user argument CI="boot".
estBootCIs(trt, t.seq, M, Y, t.est, deltat, replicates)a vector indicating treatment group
a vector of time points at each obs
matrix of mediator values
matrix of outcome values
time points at which to make the estimation
a small constant which controls the time-lag of the effect of the mediator on the outcome, half the time between two time points
number of replicates for bootstrapping confidence intervals.
boot.sebootstrapped standard error for the estimated mediation effect
CI.upperpercentile bootstrapped CI upper limit for the estimated mediation effect
CI.lowerpercentile bootstrapped CI lower limit for the estimated mediation effect