Talk:Circular error probable

message: I propose deleting all the unreferenced and unreference-able material about CEPs for particular systems and refocusing the article on the CEP concept.
Any objecions? ComputerGeezer (talk) 20:13, 17 January 2008 (UTC)
thread_title:  Proposed re-focus 

message: The last paragraph is wrong.  CEP is not based on a normal distribution.  It is in fact a much more general statistic that doesn't pre-suppose and underlying statistical distribution.  CEP can generated using all sorts of distibutions. (Jeff the Baptist (talk) 14:55, 8 July 2008 (UTC)
thread_title: CEP and the Normal Distribution

message: I've been "bold" and tried to focus this article a bit, showing where the "normal" came from and how it relates to the MSE version of CEP. I think the article is more readable now. ComputerGeezer (talk) 00:42, 21 August 2008 (UTC)
thread_title: Rewrite

message: The formula given in the last paragraph of this page, at least as I understand it, can't be right.  It can be shown with a simple Monte Carlo simulation that if sigma_x=sigma_y, and you assume a Gaussian distribution, that the median of the distribution in r (and hence the CEP) is about 1.1774*sigma.  Furthermore, this is a case where the integral can be done analytically and the result is the same.  If the formula is used as given on the page it yields 1.41*sigam.  In his 1997 Master Thesis, "A Comparison of Circular Error Probable Estimators for Small Samples", Charles Williams outlines a set of approximations that work reasonably well.  CEP ~ 0.563* sigma_l+.614*sigma_s where sigma_l is the larger standard deviation and sigma_s is the smaller.  There are further corrections if the samples are correlated.  Another simple measure is what Williams refers to as the Rayleigh estimate.  It is simply .9394*r^bar where r^bar is the mean radius.  
An additional problem is that the tables don't take into account ellipticity for the pattern.  The R90 and R95 values depend on the ellipticity as shown by Harter in his 1960 paper.  Again, this can be easily confirmed by Monte Carlo calculations.
In any case, what's up on the page does not appear to be correct.  There are plenty of references, going back to the original RAND paper in 1952 that could be used to back things up in this article. Should we try getting this right?  I will admit that the current article led me down the garden path for a while.
I have recently written notes on this topic "Characterizing rifle performance using circular error probable measured via a flatbed scanner"  that are found at www.statshooting.com - Any objection to updating the math in the manner outlined in the paper?
Cfmcmillan (talk) 23:22, 26 October 2008 (UTC)
thread_title:  Math errors on this page 

message: GPS accuracy is often given using CEP. --193.40.242.97 (talk) 17:07, 23 October 2009 (UTC)
thread_title:  GPS 

message: Currently the article (intro) states that CEP "is defined as the radius of a circle, centered about the mean, whose boundary is expected to include the landing points of 50% of the rounds." and later that "While 50% is a very common definition for CEP, the circle dimension can be defined for percentages" (I think the word 'other' is missing here). The first one is sourced to "Circular Error Probable (CEP), Air Force Operational Test and Evaluation Center Technical Paper 6, Ver 2, July 1987, p. 1" while the second is not sourced at all. To the best of my knowledge however, CEP is not "fixed" at 50% but can be any value, with 35, 50 and 90 being the most common (somewhat depending on munition type). I haven't been able to find any online source supporting this though, but this one does somewhat. --Heb (talk) 13:09, 28 August 2013 (UTC)
replies: text: Indeed, CEP90 is a measure commonly used in remote sensing , and it would be useful if this article included such usages. Cesiumfrog (talk) 04:06, 17 August 2016 (UTC)
thread_title:  Defintion & 50% ? 

message: Cyberbot II has detected that page contains external links that have either been globally or locally blacklisted.
Links tend to be blacklisted because they have a history of being spammed, or are highly innappropriate for Wikipedia.
This, however, doesn't necessarily mean it's spam, or not a good link.
If the link is a good link, you may wish to request whitelisting by going to the request page for whitelisting.
If you feel the link being caught by the blacklist is a false positive, or no longer needed on the blacklist, you may request the regex be removed or altered at the blacklist request page.
If the link is blacklisted globally and you feel the above applies you may request to whitelist it using the before mentioned request page, or request its removal, or alteration, at the request page on meta.
When requesting whitelisting, be sure to supply the link to be whitelisted and wrap the link in nowiki tags.
The whitelisting process can take its time so once a request has been filled out, you may set the invisible parameter on the tag to true.
Please be aware that the bot will replace removed tags, and will remove misplaced tags regularly.
Below is a list of links that were found on the main page:
*http://web.archive.org/web/20110720122829/http://www.naval-technology.com/projects/vanguard/
*:Triggered by \bnaval-technology\.com\b on the local blacklist
If you would like me to provide more information on the talk page, contact User:Cyberpower678 and ask him to program me with more info.
From your friendly hard working bot.—cyberbot II NotifyOnline 12:32, 3 April 2014 (UTC)
thread_title:  Blacklisted Links Found on the Main Page