14 questions linked to/from Back transformation of an MLR model
27k views

### Back transforming regression results when modeling log(y)

I'm fitting a regression on the $\log(y)$. Is it valid to back transform point estimates (and confidence/prediction intervals) by exponentiation? I don't believe so, since $E[f(X)] \ne f(E[X])$ but ...
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1 vote
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### Smearing retransformation in r [duplicate]

I ran a regression model with the Y variable (length of stay of patients in days) log10 transformed. I would like to compare the fit of the log10 transformed model with a similar regression where the ...
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### Obtain outcome after log-transform [duplicate]

I have to get a regression model for a dataset, and it seems that the best fit is obtained by log transforming the outcome, so that I simply applied the least squares on the trasformed response vector....
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### Normal Linear Model: Prediction of original variable from log transformed variable? [duplicate]

Suppose we have observations $(x_1,y_1),\dots, (x_n,y_n)$ which for some reason cannot be modelled reasonably using a Normal Linear Model. Assume we instead model the log transformed response ...
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### What is the reason the log transformation is used with right-skewed distributions?

I once heard that log transformation is the most popular one for right-skewed distributions in linear regression or quantile regression I would like to know is there any reason underlying this ...
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### How to deal with predictions if taking log of dependent variable

I have a very basic question about linear regression. I have a dataset where the response variable is largely skewed to the right -- if I take a log of it, the distribution becomes a lot closer to ...
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### Back Transformation

If I had a response variable that was square-root transformed, and an explanatory variable that is log transformed, and I wished to back transform the model using the summary statistics below, such ...
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### Evaluation of log Vs. non log models

There are several posts on here about this question. The gist of them, as far as I understand, is that you cannot compare RMSE or MAE of two models where one is log transformed on the dependent ...
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### Log transformed dependent variable with interaction terms

I have three questions regarding a regression equation where the dependent is log transformed, a dummy $D$ is interacted with yer dummies, and other independent variables are present on the right hand ...
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### Does taking the logs of the dependent and/or independent variable affect the model errors and thus the validity of inference?

I often see people (statisticians and practitioners) transforming variables without a second thought. I've always been scared of transformations, because I worry they could modify the error ...
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1 vote