Talk:Box plot

message: If the only data I have is a box plot, can I determine the SD and SE of the mean?  Thanks  —Preceding unsigned comment added by 128.118.7.83 (talk) 13:27, 28 March 2008 (UTC)
thread_title:  New Question! 

message: I have a question. In the data you use to make the diagram, if a number is repeated, how do you put that on the graph? I'm confused.
—The preceding unsigned comment was added by 74.244.254.26 (talk) 23:08, 6 December 2006 (UTC)
replies: text: You don't put it itself in the graph.  You use it to compute the median, box edges, and whiskers.  Those quantities are the ones plotted.  Baccyak4H (Yak!) 03:13, 7 December 2006 (UTC)
thread_title:  Question! 

message: Something on parallel boxplots would be nice.  I am very new here, still feeling my way.  I can try to do something, but it might be messy, html is not my forte Plf515 23:52, 26 November 2006 (UTC)
replies: text: Done BrettMontgomery (talk) 04:29, 26 June 2011 (UTC)
thread_title:  More suggestions 

message: "Histograms and probability density functions require assumptions of the statistical distribution." What about empirical histograms and pdf's? As far as I can see these do not require any a-priori assumptions on distributions?
: I don't know who wrote that but i agree, so i've altered that section accordingly. Qwfp (talk) 17:43, 22 February 2008 (UTC)
thread_title:  Error? 

message: The current figure, Michelsonmorley-boxplot.svg, does not render correctly and could thus confuse readers. I suggest that we revert to the non-svg file R-speed_of_light_boxplot.png.
Innohead 13:06, 15 February 2007 (UTC)
thread_title:  Boxplot Figure 

message: The quartile description is wrongly formatted, with leading s but no closing . I'd fix it, but I can't decipher what the correct sentence should be, as I don't understand it and think it may be a partial delete which has become nonsensical.Lilac Soul 08:32, 20 June 2007 (UTC)
thread_title:  Formatting error 

message: Where did someone get the idea that Sheldon invented the box plot? Tukey invented the plot at least as early as 1970, when he was circulating the manuscript for Exploratory Data Analysis. He adapted the shape from a graphic invented by Mary Ellen Spear in 1952 (Tufte shows a picture of her "range chart in VDQI). Tukey modified Spear's charts in several significant ways: he used letter values instead of quartiles, he devised distribution-free quantiles for representing outliers and extreme outliers, and (with McGill) he devised confidence intervals on the median and represented them with notches.
The algorithm for producing the box plot in this article page is not Tukey's. A discussant above describes the correct algorithm. Will someone please read Tukey's EDA and correct these serious errors? As it stands, this article only contributes to the confusion over boxplot definitions and makes it seem as if anything goes. As the Frigge, Hoaglin, and Iglewicz article clearly shows, only a few statistics packages (Minitab, SYSTAT, DataDesk) get it right. 202.62.81.253 (talk) 04:15, 23 January 2008 (UTC)
replies: text: Feel free to change the article as you see fit, especially if you can include reliable sources.  However, it may be prudent to recognize that while there may be only one "right" way to do these right in the sense of doing them like (say) Tukey described, note that the method is an exploratory one, and the value is not in getting it "right" but making it useful.  Alternative implementations are not a bad thing so long as they are not attributed falsely.  Baccyak4H (Yak!) 14:34, 23 January 2008 (UTC)
replies: text: For reasons I've explained in a footnote to the article, I don't think these can really be described as "serious errors". Sampling error is always much bigger than the difference between these definitions of quartiles/hinges. And Tukey himself proposed several variations so there's no single "right" version of a boxplot (see also my comments below). Qwfp (talk) 17:41, 22 February 2008 (UTC)
replies: text: Cf your footnote: "always dwarfed by sampling variability". It is perfectly valid to use a box plot on data that are not affected by sampling error, so I'd consider "always" a bit too strong. Johannes Hüsing (talk) 12:04, 9 September 2008 (UTC)
thread_title:  Errors 

message: If the only data I have is a box plot, can I determine the SD and SE of the mean?  Thanks  —Preceding unsigned comment added by 128.118.7.83 (talk) 13:27, 28 March 2008 (UTC)
replies: text: No. Qwfp (talk) 13:53, 28 March 2008 (UTC)
thread_title:  New Question! 

message: If there is in a Figure where there is several box plots, like the first Figure in this article, should it be called boxplot or boxplots? Now in the article it is called boxplot (singular). Yebbey (talk) 04:21, 27 April 2011 (UTC)
thread_title:  About terminology: boxplot or boxplots 

message: Re: Link to my web site that I added to the Box Plot page and removed by Glrx. I agree that the link I posted is inconsistent with the WP:NOTHOWTO policy, which I am now familiar with. My intent was not to promote my own products; the link is a tutorial, potentially very useful, though there is promotional material on the page. JonPeltier (talk) 16:16, 17 August 2011 (UTC)
thread_title:  External Link to Box Plot Tutorial 

message: Shouldn't it say "median" instead of "medium" (fig. 5)?  — Preceding unsigned comment added by 12.207.23.130 (talk) 02:31, 21 October 2011 (UTC)
replies: text: There doesn't seem to be any discussion on the commons page for the image. But yes, it needs to be changed.  — Preceding unsigned comment added by 12.107.194.3 (talk) 19:53, 14 May 2012 (UTC)
replies: text:  Fixed. Glrx (talk) 01:45, 16 May 2012 (UTC)
thread_title:  Revise box plot image? 

message: Shouldn't the whiskers in Figure 3 be of equal length?  — Preceding unsigned comment added by Raywood (talk • contribs) 21:23, 2 September 2012 (UTC)
thread_title:  Figure 3 

message: The first image in the article is a very nice real-world example of… what? The annotation says it comes from the notable experiments by Michelson and Morley to determine the speed of light, but the information in the file (https://en.wikipedia.org/wiki/File:Michelsonmorley-boxplot.svg) sais:
This data is not from the Michelson-Morley experiment but from Michelson's measurement of the speed of light. See MICHELSON, A. A. (1882). 
Obviously there is a mistake in either one of the annotations!
--Uncronopio (talk) 10:00, 5 January 2017 (UTC)
thread_title:  Michelson or Michelson–Morley 

message: Since the mathematician John W. Tukey introduced this type of visual data display in 1969 ...
This contradicts the article John Tukey, which says He introduced the box plot in his 1977 book, "Exploratory Data Analysis". So, which is true? --Feldkurat Katz (talk) 01:23, 1 May 2018 (UTC)
thread_title:  Date of introduction? 

message: It is incorrect to say that individual values plotted above the upper adjacent value or below the lower adjacent value (i.e., beyond the whiskers) are necessarily outliers. They are defined by Tukey as "outside values" which may or may not be outliers.
Outliers are values that may or may not be removed from the data set after careful individual consideration.
It is however true that outliers will almost certainly appear as outside values.
See J.M. Chambers, W.S. Cleveland, B. Kleiner, P.A. Tukey, Graphical Methods for Data Analysis, 1983, Wadsworth & Brooks/Cole, ISBN 0-412-05271-7
Pg. 22 reads, in part:
"The individual outside values give the viewer an opportunity to consider the question of outliers, that is, observations that seem unusually, or even implausibly, large or small. Outside values are not necessarily outliers (indeed, the [plot in example] suggests that the [outside values shown in example plot] are not, but any outliers will almost certainly appear as outside values."  — Preceding unsigned comment added by David Buchan (talk • contribs) 16:34, 22 November 2020 (UTC)
thread_title:  Outliers versus outside values 

message: Notched box plots have variable notch height, not width. The width (left-right indentation to the sides of the box) is arbitrarily chosen to be visually pleasing, and should be consistent amongst all box plots being displayed on the same page.
--Scharleb (talk) 19:52, 16 April 2023 (UTC)
thread_title:  Notched box plot widths 

message: The first sentence refers to "skewness groups".  Is this a typo or should it be defined? DKEdwards (talk) 16:12, 5 October 2022 (UTC)
thread_title:  skewness groups? 

message: The example presents: "The recorded values are listed in order as follows (°F): 57, 57, 57, 58, 63, 66, 66, 67, 67, 68, 67."
Then it goes "the maximum recorded day temperature is 81 °F.", "The median of this ordered data set is 70 °F.".
Seems like values are missing in the example list. Mishash1990 (talk) 10:51, 29 December 2022 (UTC)
thread_title:  Possible missing values in Example without outliers