diff --git a/artificial_bee_colony/src/food.rs b/artificial_bee_colony/src/food.rs
index 547d675..3693ab5 100644
--- a/artificial_bee_colony/src/food.rs
+++ b/artificial_bee_colony/src/food.rs
@@ -5,6 +5,7 @@ use rand::Rng;
 #[derive(Debug, Clone)]
 pub struct FoodSource {
     pub fitness: f64,
+    pub function_calculation: f64,
     pub coordinates: Vec<f64>,
     pub try_counter: u128,
 }
@@ -13,6 +14,7 @@ impl FoodSource {
     pub fn get(coordinates: Vec<f64>) -> Self {
         let mut food_source = FoodSource {
             fitness: 0.0,
+            function_calculation: 0.0,
             coordinates,
             try_counter: 0,
         };
@@ -23,6 +25,7 @@ impl FoodSource {
     }
     fn fitness_function(&mut self) {
         let calculation = Self::calculate(self.coordinates.clone());
+        self.function_calculation = calculation;
         if calculation >= 0.0 {
             self.fitness = 1.0 / (1.0 + calculation);
         } else {
@@ -62,8 +65,8 @@ impl fmt::Display for FoodSource {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         write!(
             f,
-            "fitness = {}\ncoordinates = {:#?}\ntry_counter = {}\n",
-            self.fitness, self.coordinates, self.try_counter
+            "fitness = {}\nfunction_calculation = {}\ncoordinates = {:#?}\ntry_counter = {}\n",
+            self.fitness, self.function_calculation, self.coordinates, self.try_counter
         )
     }
 }
diff --git a/artificial_bee_colony/src/lib.rs b/artificial_bee_colony/src/lib.rs
index 7505dab..762637e 100644
--- a/artificial_bee_colony/src/lib.rs
+++ b/artificial_bee_colony/src/lib.rs
@@ -120,7 +120,7 @@ impl Input {
 
 pub fn give_output(
     best_food_source: FoodSource,
-    fitness_results: &[f64],
+    function_results: &[f64],
     input_run: usize,
     run_counter: usize,
 ) {
@@ -135,8 +135,8 @@ pub fn give_output(
     let mut print_buffer = vec![];
     write!(print_buffer, "[{}]\n{}\n", run_counter, best_food_source).unwrap();
     if run_counter == input_run - 1 {
-        let arithmetic_mean = arithmetic_mean(fitness_results);
-        let standard_deviation = standard_deviation(fitness_results, arithmetic_mean);
+        let arithmetic_mean = arithmetic_mean(function_results);
+        let standard_deviation = standard_deviation(function_results, arithmetic_mean);
         write!(
             print_buffer,
             "[evaluation]\narithmetic_mean = {}\nstandard_deviation = {}",
@@ -185,18 +185,18 @@ fn write_output_file(print_buffer: &[u8], run_counter: usize) {
     file.flush().unwrap();
 }
 
-fn arithmetic_mean(fitness_results: &[f64]) -> f64 {
-    let mut total_fitness_results = 0.0;
-    for fitness_result in fitness_results {
-        total_fitness_results += fitness_result
+fn arithmetic_mean(function_results: &[f64]) -> f64 {
+    let mut total_function_results = 0.0;
+    for function_result in function_results {
+        total_function_results += function_result
     }
-    total_fitness_results / fitness_results.len() as f64
+    total_function_results / function_results.len() as f64
 }
 
-fn standard_deviation(fitness_results: &[f64], arithmetic_mean: f64) -> f64 {
+fn standard_deviation(function_results: &[f64], arithmetic_mean: f64) -> f64 {
     let mut total_difference_square = 0.0;
-    for fitness_result in fitness_results {
-        total_difference_square += (fitness_result - arithmetic_mean).powi(2)
+    for function_result in function_results {
+        total_difference_square += (function_result - arithmetic_mean).powi(2)
     }
-    total_difference_square / (fitness_results.len() - 1) as f64
+    f64::sqrt(total_difference_square / (function_results.len() - 1) as f64)
 }
diff --git a/artificial_bee_colony/src/main.rs b/artificial_bee_colony/src/main.rs
index 0017955..1ac6971 100644
--- a/artificial_bee_colony/src/main.rs
+++ b/artificial_bee_colony/src/main.rs
@@ -3,7 +3,7 @@ fn main() {
     println!("Hello, world!");
 
     let input = Input::get();
-    let mut fitness_results = vec![];
+    let mut function_results = vec![];
 
     let mut food_sources = FoodSource::create_food_sources(
         input.food_source_number,
@@ -60,10 +60,10 @@ fn main() {
                 );
             }
         }
-        fitness_results.push(best_food_source.fitness);
+        function_results.push(best_food_source.function_calculation);
         give_output(
             best_food_source,
-            &fitness_results[..],
+            &function_results[..],
             input.run,
             run_counter,
         )