C Program for Least Square Method (Regression Analysis)

#include<stdio.h>

#include<conio.h>

void main()

{

float x[100],y[100],sumx=0,sumx2=0,sumy=0,sumyx=0,b,a;

int i,n;

printf("Enter n: ");

scanf("%d",&n);

printf("Enter the values:\n");

for(i=0;i<n;i++)

{

printf("Enter x[%d] and y[%d]: ",i,i);

scanf("%f%f",&x[i],&y[i]);

}

for(i=0;i<n;i++)

{

sumx=sumx+x[i];

sumx2=sumx2+x[i]*x[i];

sumy=sumy+y[i];

sumyx=sumyx+y[i]*x[i];

}

//for y=ax+b

b=(sumx2*sumy-sumyx*sumx)/(n*sumx2-sumx*sumx);

a=(n*sumyx-sumx*sumy)/(n*sumx2-sumx*sumx);

printf("\nHence, the required eqn is y = %fx + %f",a,b);

getch();

}

OUTPUT: