RMST for time-to-event data under parametric Weibull fit for data in each arm separately. Also can provide CI for RMST estimate and difference in RMST.
dat: Data frame of time-to-event data which MUST have the columns 'time', 'arm', and 'status
tau: How long of a follow-up to consider, i.e. we integrate the survival functions from 0 to tau
alpha: Confidence interval is given for (alpha/2, 1-alpha/2) percentiles
find_pval: Boolean, if TRUE then does bootstrap under the null to find p-value of mean difference and RMST difference
seed: For reproducibility
Returns
A list including out_tab (estimate and CI in both arms), trt_rmst, pbo_rmst, diff_rmst, trt_CI, pbo_CI, diff_CI. Assumes trt coded as arm 1 and placebo coded as arm 0.