diff --git a/DESCRIPTION b/DESCRIPTION
index f99a4e5..ec58a29 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -36,7 +36,8 @@ Suggests:
     pscl,
     knitr,
     rmarkdown,
-    testthat
+    testthat,
+    rstudioapi
 URL: https://github.com/qpsy/nonnest2
 VignetteBuilder: knitr
 RoxygenNote: 7.3.3
diff --git a/R/llcont.R b/R/llcont.R
index 5896c33..caa8fa1 100644
--- a/R/llcont.R
+++ b/R/llcont.R
@@ -51,7 +51,8 @@ llcont.glm <- function(x, ...){
     switch(fam,
            binomial = {
              if(is.matrix(y)) {
-               n <- apply(y, 1, sum)
+               # Optimization: Using rowSums instead of apply for faster vectorized execution
+               n <- rowSums(y)
                y <- ifelse(n == 0, 0, y[, 1]/n)
              } else {
                n <- rep.int(1, length(y))
@@ -339,7 +340,8 @@ llcont.polr <- function(x, ...) {
   idx <- matrix(0, nrow=length(y), ncol=length(x$lev))
   idx[wherey] <- 1
 
-  model.weights(m) * log(apply(idx * x$fitted.values, 1, sum))
+  # Optimization: Using rowSums instead of apply for faster vectorized execution
+  model.weights(m) * log(rowSums(idx * x$fitted.values))
 }
 
 ################################################################
@@ -407,7 +409,8 @@ llcont.lavaan <- function(x, ...){
         Mu.hat <- unclass(moments$mean)
       } else {
         ## set mean structure to sample estimates
-        Mu.hat <- apply(x@Data@X[[g]], 2, mean)
+        # Optimization: Using colMeans instead of apply for faster vectorized execution
+        Mu.hat <- colMeans(x@Data@X[[g]])
       }
       llvec[grpind] <- dmvnorm(x@Data@X[[g]], Mu.hat, Sigma.hat, log=TRUE)
 
diff --git a/tests/testthat.R b/tests/testthat.R
index dda98ed..8c36737 100644
--- a/tests/testthat.R
+++ b/tests/testthat.R
@@ -1,4 +1,6 @@
-library(testthat)
-library(nonnest2)
+if (requireNamespace('testthat', quietly = TRUE)) {
+  library(testthat)
+  library(nonnest2)
 
-test_check("nonnest2")
+  test_check('nonnest2')
+}