# Difference between revisions of "Talk:Ragged holes"

You can't really use CEP(p) since you have no idea of what percentage of holes you'll be able to find if you shoot another target.

Consider this situation. You make 100 shots. There are enough shots for which a position can be determined so that you can estimate the group center. Now you count how many shots you can find (say 30). Take half of that number-15. Now use CEP(85). Sounds good right? Dah... How many different circles can you draw that eliminate 15 of the holes? A lot. It would conceivable to find all such circles and take average position and size. Not possible work for a human, but a computer doesn't care.

If done right ragged hole measurements aren't crippling.

Herb (talk) 18:12, 1 June 2015 (EDT)

Herb: Since you took out the following you need to provide some sort of substantial criticism of it. I can't tell if what you say above is an attempt to explain it or disprove it? More than one person has agreed that this is the best practical solution to the problem it addresses:
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:
1. Set p = proportion of shots that were censored.
2. Find the smallest sigma such that CEP(p) covers the ragged hole.
I was arguing against that part in the comments above. You want a measurement that is repeatable. You could make the measurement as you suggested then use the experimental CEP(p) to estimate CEP(50). That would at least give you a consistent measure.
To me this is a convex hull type problem. Two points will probably determine a circle, at most three. More on the circle just means that the position of the centers of the shots is within the measurement slop. So you really have a very few shots on the ragged hole which will determine where the center is. In part think of this as a sighting problem where center of the line segment for the extreme spread measurement controls "sighting" the weapon. Does that give you a warm fuzzy?
It all is a matter of how many shots were taken and what percentage of the shots are in the ragged hole and so on. For example is there another hole on the target which is large and multiple shots could have snuck in? Think of it as something between covering circle in the worse case and a true CEP(50) in the best case. So even though you could consistently estimate CEP(50) you aren't consistently measuring CEP(50). So would either option work with 10 shots where 8 are in the ragged hole?
Realistically no one is going to be shooting a 100 shots at a target and left wondering where the 46 that went in the ragged hole were. 5-10 shots is probably more the norm with maybe 1-3 "disappearing." Small sample statistics suck.
Do you want it back in? If so how about:
In practice, given a target with a ragged hole it is probably adequate to take one of the two options.
(1) If there are a small number of "censored" shots, place them "evenly" inside the hole.
(2) If the number of censored shots is large then a better solution is to:
Find the smallest hole such that covers the ragged hole.
From n, the number of shots fired, and c the number outside the circle, determine CEP(n-c) for the number of holes censored by the circle.
Use the experimental CEP(p) measurement to estimate CEP(50) so that the measurement is repeatable.
I cal live with the above because to me probably adequate means use at your own risk. If you put something back in I won't change it again without agreement.
Herb (talk) 00:47, 2 June 2015 (EDT)