Ratio Error Bars
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of Percentages/Ratio of Means Tweet Welcome to Talk Stats! Join the discussion today by registering your FREE account. Membership benefits: • Get your questions answered by community gurus and expert researchers. • Exchange your learning and error bars with percentage research experience among peers and get advice and insight. Join Today! + Reply to Thread error bars for proportions Results 1 to 8 of 8 Thread: Standard Error of Percentages/Ratio of Means Thread Tools Show Printable Version Email this Page… what do error bars show Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode 12-27-201104:39 AM #1 ugm2tgh View Profile View Forum Posts Give Away Points Posts 1 Thanks 1 Thanked 0 Times in 0 how to calculate error bars in excel Posts Standard Error of Percentages/Ratio of Means Apologies if I am posting in the wrong in the wrong part of the forum. I am a Cell Biology researcher with a specific analysis question. I have searched high and low for a definitive answer without success. Any help would be very much appreciated! In many experimental circumstances we summarise triplicate repeats of two conditions (e.g. treated vs untreated with a particular drug, or temperature
How To Calculate Error Bars By Hand
A vs temperature B), whose output is a continuous variable (usually number of cells), as a mean. We express our data as a ratio of these means (e.g. treated/untreated). I would like to know how to calculate a standard error for the ratio of the means for the purpose of generating error bars on summary graphs. Below is a fictional example; Cell Types A, B, C For each cell type two conditions (treated vs untreated). Each condition has 3 replicates i.e. 18 data points overall. A mean for each triplicate is calculated. For each cell type, the mean of 'treated' is divided by mean 'untreated' to give a ratio of the two means. For the purpose of plotting summary graphs, I would like to know if it is possible to express standard deviation or standard error for this figure, or if there is a more appropriate method of generating error bars. I have attached a fictional example. Any advice would be very greatly appreciated. Thanks in advance! Attached Files Calculation Example.doc (31.5 KB, 130 views) Reply With Quote 12-27-201111:01 AM #2 trinker View Profile View Forum Posts Visit Homepage ggplot2orBust Awards: Location Buffalo, NY Posts 4,355 Thanks 1,759 Thanked 909 Times in 795 Posts Re: Standard Error of Percentages/Ratio of Means I don't have t
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How To Interpret Error Bars
Help Journal ListJ Cell Biolv.177(1); 2007 Apr 9PMC2064100 J Cell standard deviation vs standard error Biol. 2007 Apr 9; 177(1): 7–11. doi: 10.1083/jcb.200611141PMCID: PMC2064100FeaturesError bars in experimental biologyGeoff Cumming,1 Fiona Fidler,1 error propagation division and David L. Vaux21School of Psychological Science and 2Department of Biochemistry, La Trobe University, Melbourne, Victoria, Australia 3086Correspondence may also be addressed to Geoff Cumming http://www.talkstats.com/showthread.php/22484-Standard-Error-of-Percentages-Ratio-of-Means (ua.ude.ebortal@gnimmuc.g) or Fiona Fidler (ua.ude.ebortal@reldif.f).Author information â–º Copyright and License information â–ºCopyright © 2007, The Rockefeller University PressThis article has been cited by other articles in PMC.AbstractError bars commonly appear in figures in publications, but experimental biologists are often unsure how they should be used and interpreted. In this article we illustrate https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2064100/ some basic features of error bars and explain how they can help communicate data and assist correct interpretation. Error bars may show confidence intervals, standard errors, standard deviations, or other quantities. Different types of error bars give quite different information, and so figure legends must make clear what error bars represent. We suggest eight simple rules to assist with effective use and interpretation of error bars.What are error bars for?Journals that publish science—knowledge gained through repeated observation or experiment—don't just present new conclusions, they also present evidence so readers can verify that the authors' reasoning is correct. Figures with error bars can, if used properly (1–6), give information describing the data (descriptive statistics), or information about what conclusions, or inferences, are justified (inferential statistics). These two basic categories of error bars are depicted in exactly the same way, but are actually fundamentally different. Our aim is to illustrate basic properties of f
rebinning). Our issues For cross sections with error bars greater than http://www.jlab.org/~fomin/ratios/step9.html 25%, this is not a good way to get the errorbars: error=ratio*sqrt[(err_A/sigma_A)**2+(err_3He/sigma_3He)**2] Instead, we shift the 3He cross section up/down by 1 sigma and recalculate the ratio, and use those two (ratio_max, and ratio_min) to give us the error in the ratio. Unfortunately, it's asymmetric. Therefore, extracting a value for the ratio for x>2.4 (or some other error bars threshold) is not straight-forward since some points have symmetric error bars and others don't. Instead, John suggested we deal with ratios of 3He/A, where the denominator doesn't go to zero as fast, and its errorbars are usually manageable. Here, we work with symmetric errorbars until we extract the final ratio in a given x-range, then invert how to calculate it to get the A/3He ratio and calculate the asymmetric errorbars for that final number. Option 1 Take the ratio of integrated cross sections. So, add up all the 3He and A cross sections for xmin< x < xmax and take the ratio. So that ratio=sum(sigma_3He)/sum(sigma_A). 18 ... 4 ... 0.279941 +/- 0.0388449 18 ... 9 ... 0.177657 +/- 0.0242408 18 ... 12 ... 0.120225 +/- 0.0163779 18 ... 63 ... 0.0937415 +/- 0.0127339 18 ... 197 ... 0.0835292 +/- 0.0113302 Option 2 In this case, we take all the 3He/A ratios in a given x-range and perform an error-weighted average [Sum(r/err**2)/Sum(1/err**2)] 18 ... 4 ....... 0.283154 +/- 0.0384222 18 ... 9 ....... 0.17198 +/- 0.0241541 18 ... 12 ..... 0.104401 +/- 0.016072 18 ... 63 ..... 0.0817404 +/- 0.0126605 18 ... 197 ... 0.0692293 +/- 0.0110757 Decision time While close, the two methods do not yield the same answer. And the disparity grows as one goes to heavier nuclei. In the end, there can be only one.