jwdink

library('dplyr')
library('tidyr')
library('pbapply')

#' simulate()
#'
#' @param num_groups Number of groups
#' @param num_per_group Number of observations per group
#' @param true_coef The true `beta_1` in `Y_t ~ beta_0 + beta_1*X_t`
#' @param phi A function that takes Y_t-1,...,Y_t and returns Xt