Let’s have fun with Correlation :-O
Whenever you will read any post or paper related to Machine-Learning or Data-Science you will get word ‘Correlation’ many times and how it’s value is important in your model Building.
A simple definition of Correlation: A mutual relationship or connection between two or more things. (that’s layman’s definition and It should be enough most of the times ;) )
Coefficient of Correlation is just an integer, From which we understand how two or more things are related to each-other. As we discussed Coefficient of Correlation is an integer so it could be +ve or -ve and value of correlation decides how two data-sets effect each other.
Following two images tell lot about Correlation and it’s Value.
What is Covariance?
Now if you still feel that something is really missing we should talk about Variance:
Let’s Remove Co from Covariance.
Variance is Measurement of randomness. So How you would calculate Variance of Data?
Give me data:
Data = [4,5,6,7,12,20]
I will find means and subtract it from each individual- Isn’t that Mean-Deviation ? :D OMG!
Have a look at the following Picture: