It's the sum of cross products.

Selling products sometimes requires having a stroke of genius.

Then, I'll sum the cross products.

These products are selling like hot cakes.

Look what's in the numerator, sum of cross products.

And the sum of cross products are in the off diagonals.

And covariance was just sum of cross products divided by n.

Do you have scalable pricing? Are you cross selling and up selling a lot?

We then post multiply that by the cross products.

And that gives me sum of cross products. Analogous to sum of squares.

And remember we calculated that by calculating sum of cross products for X and Y. So that's represented in this shaded region here, is the sum of cross products.

You do the same exact thing to get the sum of cross products.

It's a matrix that represents the sum of squares and the sum of cross products.

So, we have the some of the squares and we have the cross products.

From that matrix of deviation scores we can get sum of squares and sum of cross products.

Gee, when you buy this product, we'll give you a 20 discount off of this other one, which most consumers would realize, ooh I'd like to have that too, and so thinking about what adjacent products, what products next to the one you're already selling customers can buy is a cross selling strategy.

I'm talking about a highschool dropout from the projects of mercy using his entrepeneurial hassle and rap skills to go from selling drugs, to selling CDs out of the trunk of his car, to selling products at Macy's.

We don't do that. But I did it here just to demonstrate the similarity of some cross products.

Cross, cross.

So in the diagonals I get sum of squares. And in the off diagonals I get sum of cross products.

Remember that was just calculating sum of cross products relative to sum of squares and X and Y. So, that's

So there's only two cross products, because we just have two predictors and one outcome.

So sum of squares X, sum of squares Y, and then some squares, sorry, some of cross products for X and Y.

One of those fission products is named xenon 135, and here is its cross section relative to two nuclear fuels.

And Z score times a Z score gives you a positive value, again contributing to the sum of cross products.

That's just like variance except it's the sum of cross products over N. And correlation is just standardized co variance.

Cross now. Cross now.

The correlation coefficient is the sum of cross products over the square root of sums of squares for x times sums of squares for y.

location of the red cross and the location of the blue cross.

. Selling it. I'm selling the Jet Ski.

So let's say we're selling, I don't know, instead of selling a million cupcakes we're only selling 500,000 cupcakes.

Selling stock.

By selling.

Selling myself?

You selling'?

I'm selling.

You selling?

He's selling Rome's reserves of grain.

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