diff --git a/Exercise09code.R b/Exercise09code.R
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+++ b/Exercise09code.R
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+# Usage: (directory_path, specified_column)
+coeffOfVar <- function(dir,colName){
+  fileList <- list.files(path = dir)
+  vectorOutput <- c()
+  for(i in fileList){
+    data <- read.table(i,header=TRUE,sep=",",stringsAsFactors=FALSE)
+    rows <- length(data$colName)
+    minRow <- 50
+    if(rows<minRow){
+      answer <- readline(prompt = "WARNING: input files have less than 50 observations. 
+                         Would you still like to calculate the coefficient of variance? 
+                         Type 'Y' for yes or 'N' for no")
+      if(answer=="Y"){
+        Sd=sd(data$colName)
+        Mean=mean(as.numeric(data$colName))
+        cov=Sd/Mean
+        vector <- c(vectorOutput, cov)
+      }
+      if(answer=="N"){
+        break
+      }
+    }else{
+      Sd=sd(data$colName)
+      Mean=mean(as.numeric(data$colName))
+      cov=Sd/Mean
+      vector <- c(vectorOutput, cov)
+    }
+  }
+  return(vectorOutput)
+}
+
+#Test code:
+coeffOfVar("~/Desktop/Biocomputing/RStudio/Biocomp_tutorial11/new",wage)
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