how to check the 'contribution' of each predictor in a linear regression

I have linear regression model, say with 5 predictors, . I wanted to know how we can perform tests regarding the 'contribution' of each predictor.

Does matlab have a function that tests all possible subsets of predictors and outputs the error?

Thanks

Answer 1

[Star Strider]

You are describing a stepwise multiple linear regression. Seee the documentation on the stepwiselm (link) function and its friends for details.