predicting waste per capita - is a gaussian model correct?
Well, this is 100% off-topic... And I wasn't planning to answer the OP's question. However, I disagree with your answer.
There is no requirement that the dependent variable in a "regression" type estimation follows a gaussian distribution.
False. It's depends on what type of '"regression" type estimation' one uses, among other things.
You need a model of the process and then use an estimation technique to estimate your model. If effects in your model are additive do not use a log transformation. If effects are multiplicative then use a log transformation.
The main question is, does the model satisfy the *assumptions*.
The choice should be determined by the mechanics of the problem and not by the statistics.
While a mechanistic understanding is definitely valuable... If the criteria for a good model vs a bad model, was whether the model was consistent with mechanistic theory/understanding, then nearly every statistical model I've seen would be a bad model. I would say, a good model is one that is useful...
If you do use a log transformation the trying to reverse the process using an exponential transformation will be biased. The extent of that bias depends on your problem and it would not be possible to estimate the significance of the bias without a much greater knowledge of the process and data.
Never heard of this before... But I do note back-transformation is not trivial, and I'm not an expert on back-transformations.
I would suggest that you consult a competent statistician.
I agree on that part...