diff --git a/R/lm.parboot.R b/R/lm.parboot.R
index 0472c2d..8364bcb 100644
--- a/R/lm.parboot.R
+++ b/R/lm.parboot.R
@@ -10,4 +10,22 @@ lm.parboot <- function(x, y, R = 1000) {
    z <- Rfast::matrnorm(n, R)
    booty <- sqrt(s) * z + est
    xx %*% booty
-}    
\ No newline at end of file
+}    
+
+
+#[export]
+lm.nonparboot <- function (x, y, R = 1000) {
+    x <- model.matrix(y ~ ., data.frame(x))
+    xx <- tcrossprod(Rfast::spdinv(crossprod(x)), x)
+    be <- xx %*% y
+    dm <- dim(x)
+    n <- dm[1]
+    p <- dm[2]
+    est <- as.vector(x %*% be)
+    res <- y - est
+    s <- Rfast::Var(res) * (n - 1)/(n - p)
+    z <- Rfast::rep_col(res, R)
+    z <- Rfast::colShuffle(z)
+    booty <- sqrt(s) * z + est
+    xx %*% booty
+}
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