Forums
New posts
Search forums
What's new
Articles
Latest reviews
Author list
Classifieds
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Install the app
Install
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Single digit E.S. dont mean squat.
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="DNADave" data-source="post: 2879139" data-attributes="member: 110467"><p>Generally, that should be true, but with ES, you could get into a case of chasing your tail. The tails of the distribution are always what we in statistics call long. This means that they extend way off into eternity in both directions. Just by random chance you could get a speed somewhere in this "eternity" area which would lead you to think that this is a poor load when in reality it was just a fluke of random chance. The SD will tell you a different story (assuming a reasonable sample size) in this case. If you had shot say a 30-50 shot string and calculated your SD in this case that SD may be perfectly acceptable but that one shot will put your ES out of acceptance.</p><p></p><p>In that scenario I just described, the ES and SD are telling you different stories and I would argue that the SD is telling a story closer to the truth.</p><p></p><p>All of this is also assuming that the distribution of shots is unimodal or single humped. If you have two (or more) modes, two (or more) humps, then that is a different story altogether. If your reloading process is under control you should have a unimodal distribution of speeds. If not, then something happened in your reloading process that you'll have to figure out.</p><p></p><p>I'm just trying to help you not spend time you shouldn't by getting sidetracked by one random fluke should that happen. If the SD and ES are telling you the same story, then great. If not, I would trust the SD more and I would inspect my distribution to make sure that there wasn't some other influence on my reloading process (so ES isn't entirely useless, it's just nowhere near as useful as the SD).</p></blockquote><p></p>
[QUOTE="DNADave, post: 2879139, member: 110467"] Generally, that should be true, but with ES, you could get into a case of chasing your tail. The tails of the distribution are always what we in statistics call long. This means that they extend way off into eternity in both directions. Just by random chance you could get a speed somewhere in this "eternity" area which would lead you to think that this is a poor load when in reality it was just a fluke of random chance. The SD will tell you a different story (assuming a reasonable sample size) in this case. If you had shot say a 30-50 shot string and calculated your SD in this case that SD may be perfectly acceptable but that one shot will put your ES out of acceptance. In that scenario I just described, the ES and SD are telling you different stories and I would argue that the SD is telling a story closer to the truth. All of this is also assuming that the distribution of shots is unimodal or single humped. If you have two (or more) modes, two (or more) humps, then that is a different story altogether. If your reloading process is under control you should have a unimodal distribution of speeds. If not, then something happened in your reloading process that you'll have to figure out. I'm just trying to help you not spend time you shouldn't by getting sidetracked by one random fluke should that happen. If the SD and ES are telling you the same story, then great. If not, I would trust the SD more and I would inspect my distribution to make sure that there wasn't some other influence on my reloading process (so ES isn't entirely useless, it's just nowhere near as useful as the SD). [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Rifles, Reloading, Optics, Equipment
Reloading
Single digit E.S. dont mean squat.
Top