**Edit, 2011 Nov 25: added a link to the Norms and Condition Numbers post. Find “Edit”.**

Let us put the Hald data to rest, by making a transformation intermediate between the raw data and the standardized data. We will merely center the data, by subtracting the means of each variable.

Some things will change, but some things will not. I learned a lot from both.

In particular, we will see – as we did with the standardized data – that the relationships among the independent variables remain. The details change, but we still have a very strong relationship among X1, X2, X3, and X4… a strong relationship between X2 and X4… and a weak relationship between X1 and X3.

These relationships will be identified, as before, in a couple of ways. The VIFs, variance inflation factors – which I recast as RSquareds using the equation

which came from the definition in this post

are what would show me that these three relationships among the raw variables still hold at the same strength, even when we center or standardize the data.

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