How do you guys calculate?????

I see what your talking about. I have found several that support the method that I use. All you have to do is use this one:
http://easycalculation.com/statistics/standard-deviation.php

and we will be in agreement!! …. .. ….. ..

Check these numbers out in your calculator:
5,10,11,14,14

Total Numbers: 5
Mean (Average): 10.8
Standard deviation: 3.70135
Variance (Standard deviation): 13.7
Population Standard deviation: 3.31059
Variance (Population Standard deviation): 10.96

The method I use results in 3.7. That could be a rounded off Standard deviation or Variance (Standard deviation) as above.
I don’t think the the following applies to our ballistics samples but I’m ready to hear any argument otherwise.

Estimating population standard deviation

One can find the standard deviation of an entire population in cases (such as standardized testing) where every member of a population is sampled. In cases where that cannot be done, the standard deviation σ is estimated by examining a random sample taken from the population. Some estimators are given below:

Average vs Standard Deviation:
http://www.naaminis.com/standev.html

EXERPTS:
“Confusion doesn’t come until someone asks if the velocity is uniform.

Modern shooters consider standard deviation as the best measure of velocity uniformity.

The secret for making smaller groups is uniformity.

Trying to measure the velocity uniformity of your ammo by chronographing only five shots is like measuring the accuracy with one five-shot group.

Although standard deviation is the best available measure of velocity uniformity, it is not good enough to be considered only measure of ammo quality. Use standard deviation numbers as indicators of uniformity, but use them along with other indicators of load performance.”

Large groups usually repeat;
Large groups with large standard deviations always repeat;
Small groups caused by luck never repeat.”

The formula I use I think got on this forum and from PA but couldn’t find it at this time. MS Excel spreadsheet I believe has this formula but MS Works has something else that did not work properly for velocities. I used he good formula in Works by breaking it into individual steps in separate cells. Works could not take a real long string such as 45-50 shots, and my Chrony only remember 32 shots so that is what I used.

Since I couldn’t find my exact source, I found another method, http://hubpages.com/hub/stddev and used it to validate what I used.

So here is the method I use:

Preparation; Average of Velocities = Sum of Velocities Divided by the Number of Shots.

The SUM of the Squares of All the Velocities, Minus (the Square of the Average of Velocities Times the Number of Shots). Then the results Divided by (the Number of Shots MINUS 1). Then take the Square Root of that number and you have the Standard Deviation.

It’s so much easier to use a spread sheet and just enter the velocities and observe the Deviation change as more Shot Velocities are entered.

The problem of using a spread sheet set up for this is that it is easy to delete or screw up a formula in any one cell. In which case it is best to start over with a fresh COPY of a MASTER COPY of the spread sheet.
Individual FORMULA are sort of hidden inside some of the cells where you enter your data and if you make an error in entry it is best to back space to get rid of the error. If you use delete in such a case, you delete the needed formula.