Error Bars Below 0
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here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us error bars in excel MathOverflow Questions Tags Users Badges Unanswered Ask Question _ MathOverflow is a question and answer site how to calculate error bars for professional mathematicians. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The error bars matlab best answers are voted up and rise to the top Is it alright for STD error bars to be below zero? up vote 1 down vote favorite 1 I have some statistical data from which I want to graph the means
Error Bars In Excel 2013
and use the standard deviations as error bars. However this produces a graph with some of the error bars passing below zero. A negative value is silly for this data (mean trip times), so I was wondering what is a sensible way to graph the data. st.statistics mathematical-writing exposition share|cite|improve this question edited Jul 6 '12 at 8:44 Federico Poloni 8,36323460 asked Nov 10 '09 at 10:50 hoju 12216 1 Perhaps you could clarify what you mean by STD? Is it standard error bars in r deviation? Also, you could use the [statistics] tag. –Sonia Balagopalan Nov 10 '09 at 12:47 1 Yes, "STD" is an unfortunate acronym. –Theo Johnson-Freyd Nov 10 '09 at 19:04 in the context of a math question, do you really need clarification what STD means? –hoju Nov 10 '09 at 20:30 add a comment| 4 Answers 4 active oldest votes up vote 7 down vote accepted Your error bars may be giving you a hint to look more closely at the distribution of your data: it may not be symmetric. For example, if your data is essentially log-normal you could work with the logs of your numbers and the problem will automatically go away. I'm not a fan of error bars. In theory they let you visually do some statistical significance estimates and perhaps give some sense of the underlying data. But there are a lot of subtleties and at least one study has found that even experienced scientists often misinterpret them. This nice blog post discusses some of the issues. If you do need to summarize the data with a few statistics, I'd argue for boxplots as a better way to represent asymmetric distributions, along with text/captions that highlight important statistical significance conclusions. share|cite|improve this answer edited Nov 8 '15 at 2:59 Scott Lawton 1032 answered Nov 10 '09 at 14:12 Martin M. W. 3,4911718 add a comment| up vote 5 down vote Perhaps means and standard deviations are the wrong way to
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Error Bars In Excel 2010
Tags Users Badges Unanswered Ask Question _ Cross Validated is a question and answer site for people interested in statistics, machine learning, data analysis, data mining, and data visualization. Join http://mathoverflow.net/questions/4840/is-it-alright-for-std-error-bars-to-be-below-zero them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top With regards to asymettric error bars, what is the correct alternative to S.E.M. when data are strictly positive and near zero? up vote 1 down vote favorite I http://stats.stackexchange.com/questions/46946/with-regards-to-asymettric-error-bars-what-is-the-correct-alternative-to-s-e-m have some data that measures how a substance decays over time. At each time point I have 4 measurements. At time points where there is a lot of substance I use the standard error for error bars and this seems standard practice. However, when the amount of substance nears zero and I have a lot of variability in the measurement the standard error indicates that the lower error bars are values less than zero and this is physically impossible for this substance. When this is the case, how should I calculate where my error bars go? I suppose I'm assuming the underlying distribution of the data is gaussian when I use standard error, but clearly the data is not gaussian when it is near zero, because I can't have negative amounts of substance. Is there another distribution I should be using? Thanks. standard-deviation standard-error error share|improve this question asked Jan 4 '13 at 5:36 wherestheforce 605 add a comment| 1 Answer 1 active oldest votes up vote 1 down vote You should consider the log-normal distribution http://en.wikipedia.org/wik
Peltier Technical Services, Inc., Copyright © 2016. I've written about Excel chart error bars in Error Bars in Excel Charts for Classic Excel and in Error Bars in Excel 2007 Charts for New Excel. Both articles contained instructions for adding custom error bar values for individual points, but judging from the emails http://peltiertech.com/custom-error-bars-in-excel-charts/ I receive, a separate article on custom error bars is needed. You cannot add custom error bar values to a single point in a chart. However, you can individual custom error bar values to all points in a plotted series. You need to put all of the individual error bar values into a range of the worksheet. I usually put these values in the same table as the actual X and Y values Manually Defining Custom Error Bars Sample Data and Charts Suppose we have the following data: X error bars and Y values, plus extra columns with positive and negative error bar values for both X and Y directions. The data is set up so that, for example, cells C2 and D2 have the values for the positive and negative horizontal (X) error bars for the point defined by X and Y values in A2 and B2. Cells E2 and F2 have the values for the positive and negative vertical (Y) error bars for this point. The series is plotted using all the data at once, with X in A2:A6 error bars in and Y in B2:6. The error bars are also drawn using all the error bar data at once: C2:C6 and D2:D6 for horizontal and E2:E6 and F2:F6 for vertical. The chart itself is easy: create an XY chart using the data in columns A and B. The protocols for adding custom error bars differ between Classic Excel and new Excel. After following the appropriate protocol below, the chart will have custom error bars on each data point, based on the additional columns of data. This chart shows just the Y error bars, to show clearly that each point has custom values different from other points: This chart shows the X and Y error bars: Important Note A single custom error bar value cannot be added to a single data point, and custom error bar values cannot be added to a series of data points one point at a time. If you select a single value for your custom error bars, this single value will be applied to all points in the series. A whole set of custom error bar values can be added to an entire series in one operation. Put your custom values into a range parallel to your X and Y values as I've done with this sample data, then use the manual technique or the utility to add all the values to the chart series in one step. New Excel (2007 and later) It is harder to apply error bars in Excel 2007 than in earlier versions. There is no convenient tab on the Format Series dialog. The Error Bar tab(s) as