diff --git a/JavaUtils/nbproject/project.properties b/JavaUtils/nbproject/project.properties
deleted file mode 100644
index d9a04f2..0000000
--- a/JavaUtils/nbproject/project.properties
+++ /dev/null
@@ -1,93 +0,0 @@
-annotation.processing.enabled=true
-annotation.processing.enabled.in.editor=false
-annotation.processing.processor.options=
-annotation.processing.processors.list=
-annotation.processing.run.all.processors=true
-annotation.processing.source.output=${build.generated.sources.dir}/ap-source-output
-build.classes.dir=${build.dir}/classes
-build.classes.excludes=**/*.java,**/*.form
-# This directory is removed when the project is cleaned:
-build.dir=build
-build.generated.dir=${build.dir}/generated
-build.generated.sources.dir=${build.dir}/generated-sources
-# Only compile against the classpath explicitly listed here:
-build.sysclasspath=ignore
-build.test.classes.dir=${build.dir}/test/classes
-build.test.results.dir=${build.dir}/test/results
-# Uncomment to specify the preferred debugger connection transport:
-#debug.transport=dt_socket
-debug.classpath=\
-    ${run.classpath}
-debug.modulepath=\
-    ${run.modulepath}
-debug.test.classpath=\
-    ${run.test.classpath}
-debug.test.modulepath=\
-    ${run.test.modulepath}
-# Files in build.classes.dir which should be excluded from distribution jar
-dist.archive.excludes=
-# This directory is removed when the project is cleaned:
-dist.dir=dist
-dist.jar=${dist.dir}/JavaUtils.jar
-dist.javadoc.dir=${dist.dir}/javadoc
-dist.jlink.dir=${dist.dir}/jlink
-dist.jlink.output=${dist.jlink.dir}/JavaUtils
-excludes=
-includes=**
-jar.compress=false
-javac.classpath=
-# Space-separated list of extra javac options
-javac.compilerargs=
-javac.deprecation=false
-javac.external.vm=true
-javac.modulepath=
-javac.processormodulepath=
-javac.processorpath=\
-    ${javac.classpath}
-javac.source=11
-javac.target=11
-javac.test.classpath=\
-    ${javac.classpath}:\
-    ${build.classes.dir}
-javac.test.modulepath=\
-    ${javac.modulepath}
-javac.test.processorpath=\
-    ${javac.test.classpath}
-javadoc.additionalparam=
-javadoc.author=false
-javadoc.encoding=${source.encoding}
-javadoc.html5=false
-javadoc.noindex=false
-javadoc.nonavbar=false
-javadoc.notree=false
-javadoc.private=false
-javadoc.splitindex=true
-javadoc.use=true
-javadoc.version=false
-javadoc.windowtitle=
-# The jlink additional root modules to resolve
-jlink.additionalmodules=
-# The jlink additional command line parameters
-jlink.additionalparam=
-jlink.launcher=true
-jlink.launcher.name=JavaUtils
-meta.inf.dir=${src.dir}/META-INF
-mkdist.disabled=true
-platform.active=default_platform
-run.classpath=\
-    ${javac.classpath}:\
-    ${build.classes.dir}
-# Space-separated list of JVM arguments used when running the project.
-# You may also define separate properties like run-sys-prop.name=value instead of -Dname=value.
-# To set system properties for unit tests define test-sys-prop.name=value:
-run.jvmargs=
-run.modulepath=\
-    ${javac.modulepath}
-run.test.classpath=\
-    ${javac.test.classpath}:\
-    ${build.test.classes.dir}
-run.test.modulepath=\
-    ${javac.test.modulepath}
-source.encoding=UTF-8
-src.dir=src
-test.src.dir=test
diff --git a/JavaUtils/src/id/ac/ub/filkom/rendicahya/utils/array/operators/StandardDeviationCalculator.java b/JavaUtils/src/id/ac/ub/filkom/rendicahya/utils/array/operators/StandardDeviationCalculator.java
index 898a3ac..0b437b6 100644
--- a/JavaUtils/src/id/ac/ub/filkom/rendicahya/utils/array/operators/StandardDeviationCalculator.java
+++ b/JavaUtils/src/id/ac/ub/filkom/rendicahya/utils/array/operators/StandardDeviationCalculator.java
@@ -5,4 +5,119 @@
 // Input 1: [1, 4, 8, 2, 5]
 // Output: 2.7386127875258
 public class StandardDeviationCalculator implements ArrayToDoubleReducer {
-}
+
+    @Override
+    public double reduce(byte[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+    }
+
+    @Override
+    public double reduce(short[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+        
+    }
+
+    @Override
+    public double reduce(int[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+       
+    }
+
+    @Override
+    public double reduce(long[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+        
+    }
+
+    @Override
+    public double reduce(float[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+        
+    }
+
+    @Override
+    public double reduce(double[] input) {
+        double sum = 0, standardDeviation = 0;
+        int length =  input.length;
+
+        for(double num : input) {
+            sum += num;
+        }
+
+        double mean = (sum/length);
+
+        for(double num: input) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation/length);
+       
+    }
+    }
+
+ 
+