Difference between revisions of "Ragged holes"
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| − | Throughout the rest of this site we assume that we can measure the location of each and every shot on a target. It is possible | + | Throughout the rest of this site we assume that we can measure the location of each and every shot on a target. It is possible — and with larger shot groups and/or more precise rifles increasingly likely — that the target will exhibit a "ragged hole" into which one or more shots has disappeared. |
This is known as a "center-censored" sample. [http://stats.stackexchange.com/questions/76533/estimating-variance-of-center-censored-normal-samples A detailed explanation and discussion of the problem is here], but presently no good mathematical solutions have come up. | This is known as a "center-censored" sample. [http://stats.stackexchange.com/questions/76533/estimating-variance-of-center-censored-normal-samples A detailed explanation and discussion of the problem is here], but presently no good mathematical solutions have come up. | ||
Revision as of 23:07, 13 June 2014
Throughout the rest of this site we assume that we can measure the location of each and every shot on a target. It is possible — and with larger shot groups and/or more precise rifles increasingly likely — that the target will exhibit a "ragged hole" into which one or more shots has disappeared.
This is known as a "center-censored" sample. A detailed explanation and discussion of the problem is here, but presently no good mathematical solutions have come up.
In practice, given a target with a ragged hole and a small number of "censored" shots, it is probably adequate to place them evenly inside the hole. If the number of censored shots is large a better solution is to:
- Set p = proportion of shots that were censored.
- Find the smallest sigma such that CEP(p) covers the ragged hole.
The best solution is to avoid this problem in the first place: Shoot no more than three rounds per target, and then aggregate them into a data set. Software to automate this process exists, e.g.,
- OnTarget Target Data System - uses coded target sheets that can be scanned to automatically aggregate one shot per aiming point.
Another easy and powerful approach is to use Brent Danielson's clever 2-shot method of generating and analyzing data.
