All Questions
Tagged with logarithm back-transformation
13
questions
3
votes
1
answer
186
views
Back Transforming log-log Model for Prediction
I have a model that is log-log and I would like to make raw predictions of $Y$ with it:
$\ln(Y) = B_0 + B_1\ln(X)$
All answers and articles I have found concerning back transforming for prediction ...
- 73
0
votes
1
answer
125
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Interpreting linear mixed effect model results with log transformed dependent variable and log transformed predictor w/ normal predictors as well
I have a linear mixed effect model that I built using longitudinal country level data to help me predict TB incidence based on country level diabetes prevalence, HIV incidence, prevalence of ...
- 11
0
votes
0
answers
269
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regression question: backtransforming MAPE for log(y)
I'm fitting a linear regression between two variables and to reduce the problem of heteroskedasticity I have log-transformed the outcome variable y.
However, this makes it difficult for me, a non ...
0
votes
1
answer
49
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Interpreting log multiple linear regression, backtransformations?
I'm investigating adherence to a special diet (that is scored from 0-18) in relation to C-reactive protein level and am in the process of building multiple linear regression models:
To achieve a ...
- 1
0
votes
0
answers
20
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First difference in logs transformation produces biased results on back-transformation [duplicate]
I have a strongly trended series where the trend appears to be exponential and I believe the errors tend to be proportional to the current value. In order to convert it to a stationary series for ...
- 3,157
2
votes
1
answer
2k
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Back transformed Median of log normal data, not equal to median of original data
l was working with these data:
160,320,160,160,320,320,160,320,160,320,160,320.
I needed to calculate the median so decided to calculate while the data was log transformed and I would just back ...
- 95
0
votes
0
answers
335
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Back-transformation of coefficients in a log-log model, and a model with a boxcox transformed y
There's a number of posts out there on back-transformations but none that I've been able to use to answer this problem, internet searches are returning surprisingly little on the issue of back-...
- 11
0
votes
0
answers
861
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Back-Transformation for Ln(X+1) of zero rich data
I have seen and read several similar questions, but mine pertains specifically to zero rich data.
I will be back transforming my data based on a first order Taylor series approximation. As outlined ...
- 86
0
votes
1
answer
98
views
Log transformed data
When you log transform data what is being tested on the original scale of the data? And why can we use our log transformed data to answer our scientific question?
We are looking at data comparing ...
- 101
2
votes
0
answers
577
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Interpreting forecast predictions of log transformed data
Using the forecast function in R, I make a 1-step prediction for a log-transformed data set Y, ( Y = log(X) ). This prediction gives me a mean and a 95% prediction interval.
How valid is this ...
- 21
7
votes
1
answer
19k
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How to back-transform a log transformed regression model in R with bias correction
I have created a model to predict the number of people with a certain characteristic (Y) based on predictor variables $X_1$, $X_2$, $X_3$, $X_4$. The model is a multiple linear regression and both the ...
- 73
3
votes
1
answer
2k
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back transformation of log means and log standard deviations
I have a set of values reported as the 'log mean'. I know from elsewhere in the text that it is the natural log that is being referred to. I'm trying to ascertain if there is a way I can derive the ...
- 45
1
vote
1
answer
4k
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Back transformation of log10 transformed data in SPSS
I have transformed my quantitative variable by using the log10 function in order to run some parametric tests (ANOVA) but when I want to make pairwise comparisons ...
