# What means "1/X weighted multiple regression"

#### alex84

##### New Member
What means 1/X weighted multiple regression?
Is it just WLS with weights = "1/X" or I'm missing smth?

#### Dragan

##### Super Moderator
What means 1/X weighted multiple regression?
Is it just WLS with weights = "1/X" or I'm missing smth?

It appears that what is being discussed is heteroscedasticity in the context of where the variance of the error term (u) is proportional to the square of the independent variable X…i.e. E[u^2] = Sigma^2*X^2.

As such, you transform the model by using 1/X as:
Y/X = b0/X + b1 + u/X

so that E[(u/X)^2] = 1/X^2 * E[u^2] = Sigma^2.