diff --git a/java-numbers-4/pom.xml b/java-numbers-4/pom.xml
new file mode 100644
index 0000000000..e1722fb039
--- /dev/null
+++ b/java-numbers-4/pom.xml
@@ -0,0 +1,52 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>java-numbers-4</artifactId>
+    <name>java-numbers-4</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>${vavr.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>java-numbers-4</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <vavr.version>0.10.2</vavr.version>
+        <commons.version>3.9</commons.version>
+        <assertj.version>3.6.1</assertj.version>
+    </properties>
+
+</project>
diff --git a/java-numbers-4/src/main/java/com/baeldung/probability/MaleHeightGenerator.java b/java-numbers-4/src/main/java/com/baeldung/probability/MaleHeightGenerator.java
new file mode 100644
index 0000000000..ed3fb8a578
--- /dev/null
+++ b/java-numbers-4/src/main/java/com/baeldung/probability/MaleHeightGenerator.java
@@ -0,0 +1,17 @@
+package com.baeldung.probability;
+
+import org.apache.commons.math3.distribution.NormalDistribution;
+
+public class MaleHeightGenerator {
+    private static final double MEAN_HEIGHT = 176.02;
+    private static final double STANDARD_DEVIATION = 7.11;
+    private static NormalDistribution distribution =  new NormalDistribution(MEAN_HEIGHT, STANDARD_DEVIATION);
+
+    public static double generateNormalHeight() {
+        return distribution.sample();
+    }
+
+    public static double probabilityOfHeightBetween(double heightLowerExclusive, double heightUpperInclusive) {
+        return distribution.probability(heightLowerExclusive, heightUpperInclusive);
+    }
+}
diff --git a/java-numbers-4/src/main/java/com/baeldung/probability/RandomInvoker.java b/java-numbers-4/src/main/java/com/baeldung/probability/RandomInvoker.java
new file mode 100644
index 0000000000..66f82022ea
--- /dev/null
+++ b/java-numbers-4/src/main/java/com/baeldung/probability/RandomInvoker.java
@@ -0,0 +1,19 @@
+package com.baeldung.probability;
+
+import io.vavr.Lazy;
+
+import java.util.SplittableRandom;
+import java.util.function.Supplier;
+
+public class RandomInvoker {
+    private final Lazy<SplittableRandom> random = Lazy.of(SplittableRandom::new);
+
+    public <T> T withProbability(Supplier<T> positiveCase, Supplier<T> negativeCase, int probability) {
+        SplittableRandom random = this.random.get();
+        if (random.nextInt(1, 101) <= probability) {
+            return positiveCase.get();
+        } else {
+            return negativeCase.get();
+        }
+    }
+}
diff --git a/java-numbers-4/src/test/java/com/baeldung/probability/RandomInvokerUnitTest.java b/java-numbers-4/src/test/java/com/baeldung/probability/RandomInvokerUnitTest.java
new file mode 100644
index 0000000000..b08c086e30
--- /dev/null
+++ b/java-numbers-4/src/test/java/com/baeldung/probability/RandomInvokerUnitTest.java
@@ -0,0 +1,24 @@
+package com.baeldung.probability;
+
+import org.assertj.core.data.Offset;
+import org.junit.Test;
+
+import java.util.stream.Stream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class RandomInvokerUnitTest {
+    @Test
+    public void givenProbability_whenInvoked_invokeWithProbability() {
+        RandomInvoker randomInvoker = new RandomInvoker();
+
+        int numberOfSamples = 1_000_000;
+        int probability = 10;
+        int howManyTimesInvoked = Stream.generate(() -> randomInvoker.withProbability(() -> 1, () -> 0, probability))
+                .limit(numberOfSamples)
+                .mapToInt(e -> e).sum();
+        int monteCarloProbability = (howManyTimesInvoked * 100) / numberOfSamples;
+
+        assertThat(monteCarloProbability).isCloseTo(probability, Offset.offset(1));
+    }
+}
diff --git a/pom.xml b/pom.xml
index 5ed3791760..b110cb0fe0 100644
--- a/pom.xml
+++ b/pom.xml
@@ -343,18 +343,18 @@
                 <module>animal-sniffer-mvn-plugin</module>
                 <module>annotations</module>
                 <module>antlr</module>
-                
-                <module>apache-cxf</module>  
-                <module>apache-libraries</module>              
-                <module>apache-olingo/olingo2</module>                
-                <module>apache-poi</module>                
+
+                <module>apache-cxf</module>
+                <module>apache-libraries</module>
+                <module>apache-olingo/olingo2</module>
+                <module>apache-poi</module>
                 <module>apache-rocketmq</module>
-                <module>apache-shiro</module>             
+                <module>apache-shiro</module>
                 <module>apache-spark</module>
                 <module>apache-tapestry</module>
                 <module>apache-thrift</module>
                 <module>apache-tika</module>
-                <module>apache-velocity</module>             
+                <module>apache-velocity</module>
 
                 <module>asciidoctor</module>
                 <module>asm</module>
@@ -443,7 +443,8 @@
                 <module>java-lite</module>
                 <module>java-numbers</module>
                 <module>java-numbers-2</module>
-		<module>java-numbers-3</module>
+                <module>java-numbers-3</module>
+                <module>java-numbers-4</module>
                 <module>java-rmi</module>
                 <module>java-spi</module>
                 <module>java-vavr-stream</module>
@@ -856,18 +857,18 @@
                 <module>animal-sniffer-mvn-plugin</module>
                 <module>annotations</module>
                 <module>antlr</module>
-              
-                <module>apache-cxf</module> 
-                <module>apache-libraries</module>                             
-                <module>apache-olingo/olingo2</module>                
-                <module>apache-poi</module>                
+
+                <module>apache-cxf</module>
+                <module>apache-libraries</module>
+                <module>apache-olingo/olingo2</module>
+                <module>apache-poi</module>
                 <module>apache-rocketmq</module>
-                <module>apache-shiro</module>                
+                <module>apache-shiro</module>
                 <module>apache-spark</module>
                 <module>apache-tapestry</module>
                 <module>apache-thrift</module>
                 <module>apache-tika</module>
-                <module>apache-velocity</module>                
+                <module>apache-velocity</module>
 
                 <module>asciidoctor</module>
                 <module>asm</module>
@@ -956,6 +957,7 @@
                 <module>java-numbers</module>
                 <module>java-numbers-2</module>
                 <module>java-numbers-3</module>
+                <module>java-numbers-4</module>
                 <module>java-rmi</module>
                 <module>java-spi</module>
                 <module>java-vavr-stream</module>