Question

prove that summation into x minus x is equals to zero​

Answer 1

Step-by-step explanation:

The sum of the deviations from the mean of a measurement is always equal to 0. The proof is as follows:

Σ(xi−x¯)=Σxi−Σx¯=Σxi−x¯Σ1=Σxi−x¯.n=Σxi−Σxi=0

Σ(xi−x¯)=Σxi−Σx¯=Σxi−x¯Σ1=Σxi−x¯.n=Σxi−Σxi=0

In a regression however it s the sum of the Squared Deviations of the Errors that is minimized (i.e. the sum of the of squares of actual y value minus predicted y value) which does not neccesarily have to be 0.