Bootstrap model coefficients and standard errors
bootstrap_ols(Y = NULL, X = NULL, stratify = NULL)list with two elements, betas = list of beta_coefficients (D dimensional vectors);
normed_betas = tibble with the norm of the non-intercept coefficients
vector of regression model's dependent variable (embedded context)
data.frame of model independent variables (covariates)
covariates to stratify when bootstrapping