Why we require Correlation

%Code:

clc

clear all

close all

x=[43 21 25 42 57 59];

a1=mean(x);

z=[];

for i=1:length(x)

    z=[z (x(i)-a1)^2];

end

s1=sum(z);

s1=s1/(length(x)-1);

s1=sqrt(s1);

y=[99 65 79 75 87 81];

a2=mean(y);

z=[];

for i=1:length(y)

    z=[z (y(i)-a2)^2];

end

s2=sum(z);

s2=s2/(length(x)-1);

s2=sqrt(s2);

x=x-a1;

y=y-a2;

ak=x*y';

cova1=ak/(length(x)-1);

corr1=cova1/(s1*s2);

x=2*[43 21 25 42 57 59];

a1=mean(x);

z=[];

for i=1:length(x)

    z=[z (x(i)-a1)^2];

end

s1=sum(z);

s1=s1/(length(x)-1);

s1=sqrt(s1);

y=2*[99 65 79 75 87 81];

a2=mean(y);

z=[];

for i=1:length(y)

    z=[z (y(i)-a2)^2];

end

s2=sum(z);

s2=s2/(length(x)-1);

s2=sqrt(s2);

x=x-a1;

y=y-a2;

ak=x*y';

cova2=ak/(length(x)-1);

corr2=cova2/(s1*s2);