How To Calculate Extreme Spread In Excel

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What do these terms mean?
Extreme Spread and Std Deviation?
Thery are both terms from statistics and both are used to indicate the extent of dispersion in a group of values. So, in terms of shooting, they could exist used to indicate how big a group was.
Extreme spread would be the altitude between the two nearly widely separated holes on the target.

This is a pretty rough measure since it uses merely ii pieces of information. Standard difference is a much more sophisticated measure of dispersion, since it makes use of all the available data.

It assumes a normal distribution - the well-known 'bell curve' - and with such a distribution nosotros tin can say with confidence that 95% of the items will lie within slightly less than ii standard deviations on either side of the centre.

And then, going back to shooting a group, the smaller the standard deviation, the tighter the group. If 95% of the holes fall inside a 12 inch circle, you have a standard deviation of roughly iii inches - a 12 inch circle amounting to 2 standard deviations on either side of the centre. Clearly, if you just looked at extreme dispersion, one flyer could give you quite the wrong impression about an otherwise tight group.

Other measures of dispersion are used - the 50% circular error probability measure was ordinarily used in assessing the accurateness of free-fall bombing, for example.
They don't let 'em tech Statistics at Auburn.

GO DAWGS!
Aut,
Both are terms used a lot by handloaders to guage/measure the uniformity of the loads they brand.
Short answer:
Remember pocket-size numbers for either/both as beingness better.
Longer:
SD is a mensurate of uniformity. An capricious numerical value is assigned (usually by the inner working of a good chronograph) to an capricious number of shots fired through the "Screens". The end result is how uniform each shot compares to the "standard", and the departure is how far off of that "standard" the gross string is.

Farthermost spread:
Highest velocity minus lowest velocity for the cord fired over the screens.

Little more:
If you read Mr. Camps first-class range reports, y'all'll note he clocks most of his loads, and lists the SD and Farthermost spread for the different ammunition he fires. Since Mr. Campsite is an first-class (very very very consistant) shooter, I like to play a little game with his reports to see how the results compare to what I believe they should be,,,earlier I look at the pictures of his targets.

It's interesting to note, that on paper ie: loads with small numbers, usually show the tightest groups when I scroll down to check the targets.
Well, it isn't arbitrary and it isn't assigned. It is calculated from the data (in this case, the chronographed velocities). Basically, it is the mean distance of each value from the mean of the values.
And then this:

Avg = 1,250 ft/sec
ES (farthermost spread) = 50
SD = 25

Would tell you that the departure between the highest and lowest velocities recorded was 50 ft/sec, and that the "average divergence" of the individual measurements from the average of those measurements was 25 ft/sec... a darn inconsistent load, in other words.

The formula for calcuating the standard deviation is attached.
Attached Files:
Curious that "extreme spread" is not simply called "range", the proper statistical term for what people have said it represents.
Beats me, just I'm always seeing ES instead of range when talking near handgun chrono results. Maybe and then information technology isn't confused with range (as in distance)?
That'southward what I was meaning to say
Thanks for the correction.
FLYERS
I am a licensed CE, (means nothing), and every bit a profession, prepare construction price estimates. Since we are talking about the futurity price of something, I ofttimes have to brand up numbers. The only data I take is from past events.

In order to accurately predict the time to come, I tin't use all by events, simply those that were "typical." Therefore, as a matter of course, in cost estimating ALL flyers are discarded from the adding of the ED (range) and the SD.

Example: If we built five stores in various parts of the state, and shop C was destroyed by a tornado during the framing phase, which meant we had to redo all of that piece of work, the final cost of shop C would exist excluded from our calculations.

A bullet can be a flyer for a multitude of reasons, like hitting a bumblebee halfway downwards range. The reason is irrelevant, flyers are atypical (at to the lowest degree we hope so!!) so they should be excluded from any calculations which are intended to provide guidance for future actions.

On the other paw, if I want to know the probability of any particular shot from my weapon hit the centre of the bullseye, and then I would include all the datsa, including the flyers.

So the actual working definition of either term, but similar about everything else in life, should exist preceeded by.."It all depends..."

God anoint and yous be careful out there.
Understandable explanation of "flyers" Geezer, but in statistics we call those "outliers" and in that location are valid rules for dealing with them without the judgement call of only tossing them out.
Thumper, Im a jr high school drib out.
ps
Im just a AU fan. Only, Those AU can handle them "DAWGS" anyday of the calendar week.

"AU Auburn University" not to be dislocated with UA Alabama Academy.

pss Thanks people.
My thoughts on Standard Divergence
I hate stats, simply have dealt with it. And so, for the unsophisticated (like me), standard deviation is basically a measure of the spread (or range) that is designed mathematically to filter out farthermost values or "outliers." I yous shoot a ii inch grouping so miss the target on your last shot your extreme spread would yet be iii feet or something, just the standard deviation would be much closer to your group.
Specifically, 67% of the values (shots) are within 1 standard departure of the mean value (the centre of your target), 95% inside ii standard deviations, and I believe 99% are inside three standard deviations.
So, if you shoot 100 rounds (all generally hit the target, not many fliers)and your standard deviation is 1 inch, 67 rounds will be inside ane inch of the middle (for a two inch circle or group), 95 will exist within 2 inches of the centre (for a four inch circle or group), and and then on.
Promise this helps a little.
FLYERS/OUTLIERS
Penforhire: Of course you are exactly right apropos statistical terms.

I used the term flyer in the sense we use it at the range, a round, that for some unknown reason, did not perform as expected or as could be predicted from the bachelor data.

Construction cost estimating is not a science, information technology is formally divers by R.S. Means, the standard of construction price values, as an art. We get to exercise things with numbers that tend to horrify mathematicians and particularly statisticians. Every quarter I have one or two in my classes, and they spend the quarter merely sitting in that location shaking their heads at what I am putting on the blackboard.

For example, if three out of four projects had unusual price factors, say a flood, a strike, and arson, respectively, with only ane of the 4 beingness constructed as planned. we would conside all three of the exceptional projects as flyers, and only use the data from the "normal" ane. I appreciate that is not kosher in statistics, merely hey, nosotros're artists!

It is one of the few fields today where the latest knowledge (i.e. brand new college graduate) is essentially useless. Most estimators do not begin to really hit their stride until they take xv or twenty years experience, and the actually good ones all have over thirty years.

Dorsum to the range. As a hunter, what I intendance nigh is how accurate my weapon is when everything goes correct. Flyers are irrelevant, group spread, (range), with the flyers excluded, is totally relevant. That allows me to make up one's mind the maximum range at which I tin call my shot.

God anoint and yous be conscientious out in that location.
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The statisticians say that standard deviation is much more than meaningful in a large sample than in the ten+round groups most of us burn over a chronograph for our average and extreme spread. Generally a small mean is also going to bear witness a pocket-sized standard difference in small samples.
Still, our scientific calculators, some chronographs and most ballistics programs evidence the sigma factor and we have gotten used to it. Smith's word of calculated variation of a given round from the mean is a good one. Even so, most statistics gives me a headache. If I present data based on 5 rounds i omit South and if I include S with the ten plus round strings I never fail to present extreme spread likewise.

On a practical level for example, if we meet ix rounds with a small extreme spread and one outlier significantly higher or lower, further experimentation might reveal a patern suggestive of poor ignition.
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spelling is aproximate has been 25 years since colleage
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