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# Standard Error Bars On Log-transformed Data

## Contents

I wish to plot this as a column plot on a log scale (y-axis) with negative values below the zero baseline, positive values above, and with the errors indicated. As an example, would you report this result for the non-normal data (t) as having a mean of 0.92 units with a 95% confidence interval of [0.211, 4.79]? Something like: 1000 100 10 * 1 * 0------------------- -1 * -10 * -100 -1000 but with bars instead of the asterisks - you get the idea. Don't use the log of the error directly! Source

Topics Analytical Statistics × 253 Questions 310 Followers Follow Data Analysis × 1,480 Questions 9,710 Followers Follow Standard Error × 121 Questions 11 Followers Follow Statistical Testing × 458 Questions 65 Referring to the attached MS Excel spreadsheet, I first log-transformed my data, x = log( |x| + 1) using the absolute values (to avoid taking the log of negative numbers) and rgreq-e85a8756e1270df07739572352ec0a3d false My Math Forum > High School Math Forum > Algebra Error bars on log-transformed plots? Sincerely, Greg :-) Attached Files Log-transformed data.xls‎ (65.5 KB, 356 views) Reply With Quote 04-25-200803:48 PM #6 Rounds View Profile View Forum Posts Posts 154 Thanks 0 Thanked 0 Times in

## Standard Error Of Log Transformed Data

END EDIT #1 EDIT #2: I tried using the quantile function to get the 95% confidence intervals: quantile(x, probs = c(0.05, 0.95)) # around [8.3, 11.6] 10^quantile(z, probs = c(0.05, 0.95)) Also check the box at the bottom of the dialog to Create a New Graph of the results. Examples: In the graph below, the X values represent the logarithm of concentration. In some situations, you can compute a rough approximation of $\text{sd}(Y)$ from $\text{sd}(\log(Y))$ via Taylor expansion. $$\text{Var}(g(X))\approx \left(g'(\mu_X)\right)^2\sigma^2_X\,.$$ If we consider $X$ to be the random variable on the log scale,

I'm suggesting you could transform this interval instead, e.g. If I understand the two parts of your question then 1) The reason for applying the log-transformation was the skew in the data (i.e. What does this mean for your interpretation though? How To Find Log Error In Physics I continued pursuing this topic (there), as I was able to upload a MS Excel file, that contained my test data, plus annotations.

If you enter concentrations, you'll need to convert them to logarithms before using nonlinear regression. Logarithmic Error Propagation log(0.5) = -0.301)]? Oct 30, 2015 Jochen Wilhelm · Justus-Liebig-Universität Gießen "What is the log-space?" I may help you here: This space maps the proportional changes. The graph of these data has a linear (not log) X axis.

Why is bench pressing your bodyweight harder than doing a pushup? Error Bars On Log Graphs The time now is 07:05 PM. Nov 10, 2015 Can you help by adding an answer? Note that in both cases, interpretation of this SD can be difficult, because in general, transformation are meant to correct for high asymmetry [log transformation is a typical example], hence confidence

## Logarithmic Error Propagation

Well, I'm glad you got your answers! Hello - I am a genetics researcher. Standard Error Of Log Transformed Data Eventually in some studies data transformation is inevitable to use proper statistical test, however when we are going to report our result, we report original data and we use data transformation to Logarithmic Error Bars Using original data, or re-transforming SE using transformed data?

Please refer here for the resolution of this problem: http://www.talkstats.com/showthread.php ... #post10965 Thanks, once again, for your replies - appreciated. this contact form Unable to understand the details of step-down voltage regulator TV episode or movie where people on planet only live a hundred days and fall asleep at prescribed time How to properly Content Search Users Tags Badges Help About FAQ Access RSS Stats API Use of this site constitutes acceptance of our User Agreement and Privacy Policy. I am trying to analyse my NGS tag sequencing data. Error Bars On Log Scale Excel

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Here is my question: when we are reporting a bar graph with error bars, how should we calculate Standard Errors (SE)? Neijenhuijs · VU University Amsterdam Once you transform your data, any and all interpretations of your analyses are based on the data in the "transformed space". Hence, I needed to keep track of this, to assign the correct sign (+ or -) in the final data values (means and upper and lower SE's of the log-transformed) data. have a peek here Greg :-) =========== Test Data: ============ SE (= SD /(n^0.5) - i.e.

All rights reserved. Logarithmic Error Calculation Next, I multiplied these log-transformed values by +1 (to indicate up-regulated genes) or -1 (to indicate down-regulated genes). normal samples from...