`luc062.c`¶

Problem Statement

For the following set of n data points (x, y), write a program to compute the correlation coefficient r.

Metadata¶

Property	Detail
Author	Amit Dutta amitdutta4255@gmail.com
Date	08 Feb 2026
License	MIT License (See the LICENSE file for details)
Difficulty	Beginner (index: 0 / 10)

Concepts¶

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Array
Pointers

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Source Code¶

#include <stdio.h>
#include <math.h>
#include <stdlib.h>

int main()
{
    double x[] = {34.22, 39.87, 41.85, 43.23, 40.06, 53.29, 53.29, 54.14, 49.12, 40.71, 55.15};
    double y[] = {102.43, 100.93, 97.43, 97.81, 98.32, 98.32, 100.07, 97.08, 91.59, 94.85, 94.65};

    int n = 11, i;
    double sum_x = 0, sum_y = 0, sum_xy = 0, sum_x2 = 0, sum_y2 = 0;
    double numerator, denominator, r;

    for (i = 0; i < n; i++)
    {
        sum_x += x[i];
        sum_y += y[i];
        sum_xy += x[i] * y[i];
        sum_x2 += x[i] * x[i];
        sum_y2 += y[i] * y[i];
    }

    numerator = (n * sum_xy) - (sum_x * sum_y);
    denominator = sqrt((n * sum_x2 - sum_x * sum_x) * (n * sum_y2 - sum_y * sum_y));

    if (denominator != 0)
        r = numerator / denominator;
    else
        r = 0; // Avoid division by zero

    printf("Correlation coefficient (r) = %.4f\n", r);

    return 0;
}

Explanation¶

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    ## What it does

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    ## Key Concepts

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    [END]

    CODE (luc062.c):

    #include <stdio.h>
    #include <math.h>
    #include <stdlib.h>

    int main()
    {
        double x[] = {34.22, 39.87, 41.85, 43.23, 40.06, 53.29, 53.29, 54.14, 49.12, 40.71, 55.15};
        double y[] = {102.43, 100.93, 97.43, 97.81, 98.32, 98.32, 100.07, 97.08, 91.59, 94.85, 94.65};

        int n = 11, i;
        double sum_x = 0, sum_y = 0, sum_xy = 0, sum_x2 = 0, sum_y2 = 0;
        double numerator, denominator, r;

        for (i = 0; i < n; i++)
        {
            sum_x += x[i];
            sum_y += y[i];
            sum_xy += x[i] * y[i];
            sum_x2 += x[i] * x[i];
            sum_y2 += y[i] * y[i];
        }

        numerator = (n * sum_xy) - (sum_x * sum_y);
        denominator = sqrt((n * sum_x2 - sum_x * sum_x) * (n * sum_y2 - sum_y * sum_y));

        if (denominator != 0)
            r = numerator / denominator;
        else
            r = 0; // Avoid division by zero

        printf("Correlation coefficient (r) = %.4f\n", r);

        return 0;
    }

luc062.c¶