Help with Multiple Linear Regression for product cannibalization.

I briefly studied this in college, and chat gpt has been very helpful, but I’m completely out of my depth and could really use your help.

We’re a master distributor that sells to all major US retailers.

I’m trying to figure out if a new product is cannibalizing the sales of a very similar product.

I’m using multiple linear regression.

Is this the wrong approach entirely?

Data base: Walmart year- Week as integer (higher means more recent), Units Sold Old …

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