Wiki / Lesson Thread: Lesson 7

Doubt Regarding Standard Deviation Score

““we can now calculate the standard deviation of the left hand side and of the right hand side and take the weighted average or the sums are the same thing to a scaler and so there is our score.””
Can anyone explain what the line exactly means here?
Specifically this - weighted average or the sums are the same thing to a scaler
The code we used to calculate the weighted standard deviation is attached.