How to evaluate in a formula that uses summatories and product of vectors?

Could someone tell me how to find beta1?

I have the following data:

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I don’t know and I don’t find anything related on google

Please help me

Edit

I tried

beta1=(n Total[x.y]-(Total[x])(Total[y]))/(n Total[x^2]-(Total[x])^2) but I got an unexpected number

-6.41769 + 0.00120621 Total[5511.93]

Why?