Correlation coefficient provide relationship between two data point or two variable. But, this relationship is linear or non-linear. Correlation coefficient gives values between -1 and +1 which defines negative linear or positive linear relationship between two variable. If its zero then does not mean there is no relationship but it may be non-linear.
Correlation coefficient between x and y is given by below equation
pxy = Cov(x,y)/sxsy
Here Cov(x,y)=E[(x-μx)(y-μy)] is coveriance. μ is mean of x or y.
Here E is expectation given by E[variable]=(Σ(variablei)*p(variablei))/N where N is total variable size.
Here E is sum of product of probability of variable and respective variable divide by total size of variable
Here standarad variable is sx = [Σ(xi-μx/σ)2]1/2 sy= [Σ(xi-μx/σ)2]1/2
Here sigma is to sum of square of difference of number of x or y from its respective mean and divide it with deviation σ. And after sum its root square to find stardarad variable.
Here standard deviation is σ=E[x2]-[E[x]]2
Leave a comment