Write C programs to implement the linear regression andpolynomial regression algorithms

Write C programs to implement the linear regression andpolynomial regression algorithms

#include<stdio.h>

#include<conio.h>

#include<math.h>

#include<string.h>

float mean(float *a, int n);

void deviation(float *a, float mean, int n, float *d, float *S);

void main(){float a[20],b[20],dx[20],dy[20];

float sy=0,sx=0,mean_x=0,mean_y=0,sum_xy=0;

float corr_coff=0,reg_coff_xy=0, reg_coff_yx=0;

char type_coff[7];

int n=0,i=0;

clrscr();

printf("Enter the value of n: ");

scanf("%d",&n);

printf("Enter the values of x and y:\n");

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

scanf("%f%f",&a[i],&b[i]);

mean_x=mean(a,n);

mean_y=mean(b,n);

deviation(a,mean_x,n,dx,&sx);

deviation(b,mean_y,n,dy,&sy); 

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

sum_xy=sum_xy+dx[i]*dy[i];

corr_coff=sum_xy/(n*sx*sy);

printf("Enter the type of regression coefficient as 'x on y' or 'y on x': ");

fflush(stdin);

gets(type_coff);

 if(strcmp(type_coff,"x on y")==1)

{

reg_coff_xy=corr_coff*(sx/sy);

printf("\nThe value of linear regression coefficient is %f",reg_coff_xy);

}

else 

if(strcmp(type_coff,"y on x")==1)

{

reg_coff_yx=corr_coff*(sy/sx);

printf("\nThe value of linear regression coefficient is %f",reg_coff_yx);

}

else

printf("\nEnter the correct type of regression coefficient.");

getch();

}

float mean(float *a, int n)

{

float sum=0, i=0;

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

sum=sum+a[i];

sum=sum/n;return (sum);

}

void deviation(float *a, float mean, int n, float *d, float *s)

{

float sum=0,t=0;

int i=0;

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

{

d[i]=a[i]-mean;

t=d[i]*d[i];

sum=sum+t;

}

sum=sum/n;

*s=sqrt(sum);

}