diff --git a/R/ANOVA.R b/R/ANOVA.R
index 21466583..bf5b0130 100644
--- a/R/ANOVA.R
+++ b/R/ANOVA.R
@@ -46,11 +46,9 @@ ANOVA <- R6Class(
                     k <- length(splited)
 
                     bar_.. <- mean(data)
-                    bar_i. <- c(
-                        lapply(
-                            splited, function(x) rep_len(mean(x), length(x))
-                        ), recursive = TRUE, use.names = FALSE
-                    )
+                    bar_i. <- unlist(lapply(
+                        splited, function(x) rep.int(mean(x), length(x))
+                    ), recursive = FALSE, use.names = FALSE)
 
                     mst <- sum((bar_i. - bar_..)^2) / (k - 1)
                     mse <- sum((data - bar_i.)^2) / (N - k)
diff --git a/R/Correlation.R b/R/Correlation.R
index d75c46c2..488d46f8 100644
--- a/R/Correlation.R
+++ b/R/Correlation.R
@@ -53,7 +53,9 @@ Correlation <- R6Class(
                 order_x <- order(x)
                 x_reorder <- x[order_x]
 
-                i_index <- c(lapply(seq_len(n - 1), seq_len), recursive = TRUE)
+                i_index <- unlist(lapply(
+                    seq_len(n - 1), seq_len
+                ), recursive = FALSE, use.names = FALSE)
                 j_index <- rep.int(seq_len(n)[-1], seq_len(n - 1))
                 x_equal <- (x_reorder[i_index] == x_reorder[j_index])
 
diff --git a/R/JonckheereTerpstra.R b/R/JonckheereTerpstra.R
index 69c0d4a6..dd9a1b35 100644
--- a/R/JonckheereTerpstra.R
+++ b/R/JonckheereTerpstra.R
@@ -34,16 +34,18 @@ JonckheereTerpstra <- R6Class(
         .define = function() {
             k <- as.integer(get_last(names(private$.data)))
             ij <- list(
-                i = c(lapply(seq_len(k - 1), seq_len), recursive = TRUE),
+                i = unlist(lapply(
+                    seq_len(k - 1), seq_len
+                ), recursive = FALSE, use.names = FALSE),
                 j = rep.int(seq_len(k)[-1], seq_len(k - 1))
             )
             private$.statistic_func <- function(data, group) {
                 where <- split(seq_along(group), group)
-                sum(c(.mapply(
+                sum(unlist(.mapply(
                     FUN = function(i, j) {
                         outer(data[where[[i]]], data[where[[j]]], "<")
                     }, dots = ij, MoreArgs = NULL
-                ), recursive = TRUE))
+                ), recursive = FALSE, use.names = FALSE))
             }
         },
 
diff --git a/R/KSampleTest.R b/R/KSampleTest.R
index 0b0b42a1..2690beef 100644
--- a/R/KSampleTest.R
+++ b/R/KSampleTest.R
@@ -21,7 +21,7 @@ KSampleTest <- R6Class(
             data <- get_list(...)
 
             private$.raw_data <- setNames(
-                c(data, recursive = TRUE, use.names = FALSE),
+                unlist(data, recursive = FALSE, use.names = FALSE),
                 rep.int(seq_along(data), vapply(data, length, integer(1)))
             )
         },
diff --git a/R/KolmogorovSmirnov.R b/R/KolmogorovSmirnov.R
index b9ae7c79..a791d44c 100644
--- a/R/KolmogorovSmirnov.R
+++ b/R/KolmogorovSmirnov.R
@@ -30,7 +30,7 @@ KolmogorovSmirnov <- R6Class(
             m <- length(private$.data$x)
             n <- length(private$.data$y)
 
-            tmp <- rep_len(1 / m, m + n)
+            tmp <- rep.int(1 / m, m + n)
             private$.statistic_func <- function(x, y) {
                 max(abs(cumsum(`[<-`(tmp, order(c(x, y)) <= m, -1 / n))))
             }
diff --git a/R/MultipleComparison.R b/R/MultipleComparison.R
index 09db2e5a..55960bb1 100644
--- a/R/MultipleComparison.R
+++ b/R/MultipleComparison.R
@@ -78,7 +78,9 @@ MultipleComparison <- R6Class(
             k <- as.integer(get_last(names(private$.raw_data)))
             private$.ij <- list(
                 i = rep.int(seq_len(k - 1), seq.int(k - 1, 1)),
-                j = c(lapply(seq.int(2, k), seq.int, to = k), recursive = TRUE)
+                j = unlist(lapply(
+                    seq.int(2, k), seq.int, to = k
+                ), recursive = FALSE, use.names = FALSE)
             )
         },
 
diff --git a/R/TwoSamplePairedTest.R b/R/TwoSamplePairedTest.R
index e35366f0..6ed1ed2d 100644
--- a/R/TwoSamplePairedTest.R
+++ b/R/TwoSamplePairedTest.R
@@ -27,7 +27,7 @@ TwoSamplePairedTest <- R6Class(
 
         .calculate_statistic = function() {
             private$.statistic <- private$.statistic_func(
-                swapped = rep_len(FALSE, nrow(private$.data))
+                swapped = rep.int(FALSE, nrow(private$.data))
             )
         },