Write a C++ Program to Calculate Standard Deviation

Calculating the standard deviation of a set of data is a common statistical operation that measures the amount of variation or dispersion in the data.

In this tutorial, we’ll show you how to write a C++ program to calculate the standard deviation of a set of numbers.

The formula to calculate the standard deviation is as follows:

standard deviation = sqrt(sum((x – mean)^2) / n)

where x is each individual value in the data set, mean is the average value of the data set, and n is the total number of values in the data set.

To write a C++ program to calculate the standard deviation, we’ll start by asking the user to enter the data set values.

We’ll then calculate the mean of the data set by adding up all the values and dividing by the total number of values.

Once we have the mean, we can use the above formula to calculate the standard deviation.

Here’s the code:

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int n;
    double x[100], sum = 0, mean, std_dev = 0;

    cout << "Enter the number of data points: ";
    cin >> n;

    cout << "Enter the data points: ";

    for(int i = 0; i < n; i++)
    {
        cin >> x[i];
        sum += x[i];
    }

    mean = sum / n;

    for(int i = 0; i < n; i++)
    {
        std_dev += pow(x[i] - mean, 2);
    }

    std_dev = sqrt(std_dev / n);

    cout << "The standard deviation is: " << std_dev << endl;

    return 0;
}

The program starts by declaring an integer variable n to store the number of data points and a double array x to store the values of the data set.

We also declare variables for the sum of the data set values, the mean, and the standard deviation.

We then prompt the user to enter the number of data points and the values of the data set. We use a for loop to read in the values of the data set and calculate the sum of the data set values.

Once we have the sum of the data set values, we can calculate the mean by dividing the sum by the total number of values.

We then use another for loop to calculate the sum of the squares of the differences between each value and the mean.

We divide this sum by the total number of values and take the square root to obtain the standard deviation.

Finally, we print out the standard deviation.