How to find relationship between two variables ?

Suppuse I have two variables/vectors X and Y, how can I find which relationship both have each other like linear/non-linear quadratic/polynomial etc ?

In addition to that, once I get the relation, how can I find the equation whoch fits in two variables X and Y ?

Answer 1

[Star Strider]

First, plot them. That will give you a good idea of how they are related.

Second, is there a known process that produced output ‘y’ from input ‘x’, or in some way relates them? If so, create a mathematical model of that process and estimate its parameters using the data.

[Koustubh Shirke]

Hi Sir,

Yes but thats the manual procedure. It would be better if we can get function or script which can recongnize its relationship as well as equation.Because I am dealing with big and multiple data sets parallely, hence manual visualization is not possible. I belive Matlab is powerful enough to do that.

[Guillaume]

Even if you can't visualise the data,as Star says it's always better to have a model, however imperfect, of the system you want to identify.

Saying that, you're probably looking for the System Identification Toolbox. I don't have it and have never used it, so can't tell you how to use it.

[Star Strider]

I have it and I have some experience with it, so if your data are signals and you want to identify a system that created it (the input signal is also required), please post the input and output sampled at the same time instants. The time vectors need to be part of each file as well.