# calculate untransformed OLS coefficient

I used OLS model to understand the effect of promotion on units sold. I have transformed the dependent variable( square root) as well as the independent variables(standard scaler).The coefficients that I have are from the transformed model. I want to build a response curve( how changing promotion by x% will impact units sold), for which I need output in untransformed form. How do I proceed ?

1. Do I calculate the untransformed coefficients? If so how ? because the dependent variable has undergone a square root transformation and as a result squaring the equation is making the calculation complex
2. Any other approach?

Thanks!

• Unfortunately, your question concerns something that doesn't exist: "how changing promotion by x% will impact units sold" is not well defined because it varies depending on the values of the explanatory variables. This is due to the initial nonlinear transformation of the response. Could you therefore try to describe in more detail what you are trying to infer from your model?
– whuber
Nov 25, 2021 at 16:27