Question

Write a program that calculates mean and standard deviation for four user entered values. The most common measures of a sample are the mean and the standard deviation. the mean is the sum of the values divided by the number of elements in the data set. The dispersion - or spread in the values - is measured by the standard deviation The equation for the mean is x¯ = x1 + x2 + · · · + xn The equation for the standard deviation is sx = √ (x1 − x¯) 2 + (x2 − x¯) 2 + · · · + (xn − x¯) 2 n − 1 Your program will have the user enter four values (all doubles), You might call them x1, x2,x3,and x4. The program will then pass these four values to a function called mean that will calculate and return the mean of the four values. The mean and the four values will then be passed to a second function called stdev which will calculate and return the standard deviation of the four values. You program should be using functions. There will be a function printHeader that prints the splash screen, a function mean that calculates the mean, a function stdev that calculates the standard deviation, and a function printResults that prints the four values, their mean, and their standard deviation Your program must also include comments with your name, the date, and a short description of the project. It must also print this information as a splash screen at the beginning of the program run. It should print like:

X: 4.00, 7.00, 1.00, 10.00

Mean: 5.50

Std Dev: 3.87

This needs to be done in C++. This is what I have so far.

//   Pound includes - will need the string and cmath libraries
#include<iostream>
#include<iomanip>
#include<cmath>
#include<string>

using namespace std;

//   Function Prototypes - Need to add three more. One for mean, one for standard deviation, and one for the printResults
void printHeader(string, string);
double mean(double, double, double, double);
double stdev(double, double, double, double, double);

int main(void) {

   // Splash Screen
   printHeader("20 October 2020", "Calculating Statistics");
  
   //   Declare and Initialize all of the variables. Will need doubles for the four data points, as well as a double for the mean // and one for the standard deviation
double x1, x2, x3, x4;
double mean;
double std;
  
   //   Prompt for entering data - you must enter four values
   cout << "Enter the first value: ";
   cin >> x1;
  
   cout << "Enter the second value: ";
   cin >> x2;
  
   cout << "Enter the third value: ";
   cin >> x3;
  
   cout << "Enter the fourth value: ";
   cin >> x4;

   // Pass the four data variables to a function that returns the mean
double m = mean (x1,x2,x3,x4);
  
   //   Pass the four data variables and the mean to a function that returns the standard deviation
   double std = stdev(m, x1, x2, x3, x4);
  

   //   Print the results
   //   Include the original values and the mean and the standard
// DO NOT PRINT IT HERE - pass the variables to a printResults function

return 0;
}  
void printResults(double m, double s, double x1, double x2, double x3, double x4){
cout << setprecision(2) << fixed << showpoint;
   cout << "Values: " << setw (10) << x1 << ", " << x2 << ", " << x3 << ", " << x4 << endl;
   cout << "Mean: " << setw (10) << m << endl;
   cout << "Standard Deviation: " << setw(10) << s << endl;

}

// Name:
// Date: 20 October 2020
// Function Definitions
void printHeader(string dueDate, string description) {
   //   Print the splash screen
   cout << endl;
   cout << "Name" << endl;
   cout << "Class" << endl;
   cout << dueDate << endl;
   cout << description << endl;
   cout << endl;

   return;
}

// Function definition for mean
double mean (double x1, double x2, double x3, double x4) {
return (x1 + x2 + x3 + x4) / 4;
}

// Function definition for standard deviation
double stdev(double m, double x1, double x2, double x3, double x4){
std = (m-x1)*(m-x1);
std + = (m-x2)*(m-x2);
std + = (m-x3)*(m-x3);
std + = (m-x4)*(m-x4);
std = std/3;
std = sqrt(std);
return std;
}

Answer 1

CODE -

//   Pound includes - will need the string and cmath libraries

#include<iostream>

#include<iomanip>

#include<cmath>

#include<string>

using namespace std;

//   Function Prototypes - Need to add three more. One for mean, one for standard deviation, and one for the printResults

void printHeader(string, string);

double mean(double, double, double, double);

double stdev(double, double, double, double, double);

void printResults(double, double, double, double, double, double);

int main(void) {

    // Call function to print Splash Screen

    printHeader("20 October 2020", "Calculating Statistics");

    

    //   Declare and Initialize all of the variables. Will need doubles for the four data points,

    //   as well as a double for the mean and one for the standard deviation.

    double x1, x2, x3, x4;

    double mean_value;

    double std_dev;

    

    //   Prompt for entering data - you must enter four values

    cout << "Enter the first value: ";

    cin >> x1;

    cout << "Enter the second value: ";

    cin >> x2;

    cout << "Enter the third value: ";

    cin >> x3;

    cout << "Enter the fourth value: ";

    cin >> x4;

    // Pass the four data variables to a function that returns the mean

    mean_value = mean(x1,x2,x3,x4);

    

    // Pass the four data variables and the mean to a function that returns the standard deviation

    std_dev = stdev(mean_value, x1, x2, x3, x4);

    // Pass the four data variables, the mean, and the standard deviation that prints the results.

    printResults(mean_value, std_dev, x1, x2, x3, x4);

    return 0;

}

// Name:

// Date: 20 October 2020

// Function Definitions

// Function definition for printing the splash screen

void printHeader(string dueDate, string description)

{

   //   Print the splash screen

   cout << endl;

   cout << "Name: " << endl;

   cout << "Class: " << endl;

   cout << dueDate << endl;

   cout << description << endl;

   cout << endl;

}

// Function definition for mean

double mean (double x1, double x2, double x3, double x4)

{

    return (x1 + x2 + x3 + x4) / 4;

}

// Function definition for standard deviation

double stdev(double m, double x1, double x2, double x3, double x4)

{

    return sqrt( ( (m-x1)*(m-x1) + (m-x2)*(m-x2) + (m-x3)*(m-x3) + (m-x4)*(m-x4) ) / 3);

}

// Function definition for printing results.

void printResults(double m, double s, double x1, double x2, double x3, double x4)

{

    cout << setprecision(2) << fixed << showpoint;

    cout << "X: " << setw (10) << x1 << ", " << x2 << ", " << x3 << ", " << x4 << endl;

    cout << "Mean:  " << setw (25) << m << endl;

    cout << "Standard Deviation:   " << setw(10) << s << endl;

}

SCREENSHOTS -

CODE -

OUTPUT -

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