Questions tagged [logarithm]
The logarithm of a number is the power to which the base must be raised to get the number.
689
questions
1
vote
0
answers
18
views
Rescale measures of association for meta-analysis (e.g., log-transformed independent variables)
I am carrying out a meta-analysis of studies evaluating the association between blood levels of specific environmental pollutants and health outcomes (binary).
Some studies reported OR/RR/HR for ...
- 11
0
votes
0
answers
33
views
log transform left data in r
I am having trouble finding the transformation operation for left/negatively skewed data. The catch? All of my values are between 0 and 1. As such, trying the standard log10 transformation command ...
- 111
1
vote
0
answers
14
views
Rejection sampling method in tail of truncated exponential distribution (answered)
See edit below as question has been answered.
I want to sample from an exponential distribution with parameter $\lambda>0$ truncated in the tail between $a>0$ and $b>0$, such that $b>a$, ...
- 33
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
2
votes
1
answer
79
views
How to do log subtract (just like logsumexp) with probabilities? [closed]
To subtract a small probability from another, this answer has constraint on log probabilities l1 > l2: Subtracting very small probabilities - How to compute? but I need a function that works for ...
- 201
0
votes
0
answers
21
views
Interpreting log transformed variables in a regression [duplicate]
I am very confused about the interpretation of log transformed variables in a regression. For example, I have a log-level model with a B0=4.95 and B1=-1.07. So my model would be log(y)=4.95 - 1.07X. ...
- 101
3
votes
2
answers
322
views
Is the exponent of the MAD (Median Absolute Deviation) of log transformed Data measuring the relative distance from median in the untransformed data?
I want to confirm whether taking the Exponent of the MAD of Log Transformed Data gives me a measure of relative distance from median of the original untransformed data.
So say I have a MAD of 0.2 for ...
- 33
1
vote
1
answer
29
views
How to interpret a regression table with logged DVs?
I'm writing a research paper and am using R for my quantitative analysis. I'm using OLS regression and have needed to perform a log transformation on my dependent variables for linearity however I don'...
- 11
1
vote
1
answer
44
views
Can we find a variance formula in terms of the log of the density? ($f(t) = e^{u(t)}$, need variance in terms of $u$)
Given a density $f(t)$, say over $t\in \mathbb{R}^n$ absolutely continuous with Lebesgue measure. Write $u(t) = \log(f(t))$ taking values in $[-\infty, \infty)$ so $f = \exp(u)$.
Can we find a general ...
- 483
0
votes
1
answer
47
views
plotting log-transformed data, but running statistics on raw data?
I intend to compare differences between means of eight groups. The differences between some of the means are only visible when I plot (in a box plot) the log-transformed data. However, I am unsure as ...
1
vote
1
answer
86
views
Simple example of Log-Sum-Exp trick for continuous case
I am trying to confirm my understanding of how to apply the [Log-Sum-Exp trick to recover a posterior distribution from a log-posterior distribution. I want to consider a simple example from a model I ...
- 195
0
votes
0
answers
27
views
Recovering normalized posterior distribution from log-posterior
For a Bayesian estimation problem that I am working on, where I update the log-posterior (many times based on data) instead of the posterior itself using Bayes rule. I find the following (rather ...
- 195
1
vote
1
answer
35
views
Can log2 be substituted with ln in logDice association measure?
I am currently doing collocational analysis in the Russian National Corpus, to be precise the Russian national news subcorpus, to see what is the most significant collocates of the lemma "gay&...
- 13
0
votes
0
answers
15
views
Is there a statistical reason why I have diagonal lines in log2FC correlation plots?
I have created a de novo RNA-seq assembly using Trinity with samples from 4 treatment groups and then ran a DEG analysis on each pairwise combination of the 4 groups. Then, I looked at how DEGs that ...
- 1
2
votes
1
answer
175
views
