diff --git a/NAMESPACE b/NAMESPACE
index d75f824..c1a7cea 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -1 +1,2 @@
 exportPattern("^[[:alpha:]]+")
+importFrom("stats", "quantile")
diff --git a/R/meanimpute.R b/R/meanimpute.R
index cc7cf5e..9023102 100644
--- a/R/meanimpute.R
+++ b/R/meanimpute.R
@@ -1,4 +1,6 @@
 #' Meanimputation
+#' Calculates mean of a given vector, ignores NA values.
+#' @param x A vector
 #' @export
 meanimpute <- function(x) {
   x[is.na(x)] <- mean(x, na.rm = TRUE)
diff --git a/R/transform_log.R b/R/transform_log.R
new file mode 100644
index 0000000..c9045b9
--- /dev/null
+++ b/R/transform_log.R
@@ -0,0 +1,18 @@
+#' transform_log 
+#' Transform numerical values into their log values
+#' @param x A vector
+#' @return logarithm of x
+#' @examples
+#' transform_log(c(NA,0,-1,exp(2)))
+#'@export 
+transform_log<-function(x){
+  if(!is.numeric(x))stop("function is expecting only numeric values")
+  x_nan<-is.na(x)
+  x[x_nan]<-1
+  ifelse(x<0,"OK", warning("input vector contains negative values, turned into NA"))
+  y<-log(x[x>=0])
+  x[x>=0]<-y
+  x[x<0]<-NA
+  x[x_nan]<-NA
+  x
+}
\ No newline at end of file
diff --git a/R/windsorize.R b/R/windsorize.R
index b4e15e6..85044f8 100644
--- a/R/windsorize.R
+++ b/R/windsorize.R
@@ -1,10 +1,23 @@
 #' Windsorize
 #'
-#' Do some windsorization.
+#'
+#' Transform all outliner data to
+#' (1-p)/2 percentile value for lower outliers and 
+#' (1+p)/2 for higher outliers.
+#' 
+#' @param x A vector.
+#' @param p A quantile.
+#' @return inuput vector x with trimmed outliers by (1-p) percentile.
+#' @examples 
+#' windsorize(rnorm(100,0,1))
 #' @export
 windsorize <- function(x, p = .90) {
-  q <- quantile(x, p)
-  x[x >= q] <- q
+  if(is.null(x))stop("vector is empty")
+  y<-x[!is.na(x)]
+  if(length(y)==0)stop("vector contains only NAs")
+  q_max <- quantile(y, (1+p)/2)
+  q_min<- quantile(y,(1-p)/2)
+  x[x >= q_max] <- q_max
+  x[x<= q_min]<-q_min
   x
-}
-
+}
\ No newline at end of file
diff --git a/man/meanimpute.Rd b/man/meanimpute.Rd
index 8139e8f..77f2fbc 100644
--- a/man/meanimpute.Rd
+++ b/man/meanimpute.Rd
@@ -6,6 +6,9 @@
 \usage{
 meanimpute(x)
 }
+\arguments{
+\item{x}{A vector}
+}
 \description{
 Meanimputation
 }
diff --git a/man/transform_log.Rd b/man/transform_log.Rd
new file mode 100644
index 0000000..c42f726
--- /dev/null
+++ b/man/transform_log.Rd
@@ -0,0 +1,22 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/transform_log.R
+\name{transform_log}
+\alias{transform_log}
+\title{transform_log 
+Transform numerical values into their log values}
+\usage{
+transform_log(x)
+}
+\arguments{
+\item{x}{A vector}
+}
+\value{
+logarithm of x
+}
+\description{
+transform_log 
+Transform numerical values into their log values
+}
+\examples{
+transform_log(c(NA,0,-1,exp(2)))
+}
diff --git a/man/windsorize.Rd b/man/windsorize.Rd
index 832c3cb..dcabd36 100644
--- a/man/windsorize.Rd
+++ b/man/windsorize.Rd
@@ -6,6 +6,19 @@
 \usage{
 windsorize(x, p = 0.9)
 }
+\arguments{
+\item{x}{A vector.}
+
+\item{p}{A quantile.}
+}
+\value{
+inuput vector x with trimmed outliers by (1-p) percentile.
+}
 \description{
-Do some windsorization.
+Transform all outliner data to
+(1-p)/2 percentile value for lower outliers and 
+(1+p)/2 for higher outliers.
+}
+\examples{
+windsorize(rnorm(100,0,1))
 }