Standard deviation the how to for the Cheap guys.

[frankythefly]

Standard deviation the how to for the Cheap guys. (Using Excel)

What you will need

1) a cheap chronograph that doesn't give you standard deviation(or if you want to check if your chrono is right)

2) a recent 10 shot string of data (Write down your velocity for 10 shots)

3) A computer with a database program Excel, Minitab, openoffice etc. (if you don't have any of these you will have to do it the old fashion way pen and paper)

Standard Deviation is one of those things that is a pain to calculate and not a lot of people truly do correctly.

Defintion: It shows how much variation there is from the "average" (mean, or expected/budgeted value). A low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data is spread out over a large range of values. (straight from wikipedia)

If you look online you will find lots of different complex formulas and all kind of crazy math jargon. But the way I will show you doesn't require any match skills only basic computer skills.
What you will need to do is open up excel(this is for 2007) with your piece of paper containing your data.
Enter your data in the first column like the example I have shown.

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

Once you have input all the data you will need to install an add-in to your excel some of you may have it installed but most likely not. Once you install it you don't ever have to install it again. Go to the Microsoft emblem in the top left corner of excel. Click it and drop down all the way to the bottom to where it says excel options. Look at picture.

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

Once the options menu opens up click the option that says add-ins look at picture:

Then select the Analysis tool pack vba should be close to the top. A new window will open looking like this:

Make sure Analysis tool pack and Analysis tool pack vba are checked and press ok.

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

It should then install the Analysis tool pack. When it is done you will get a new button on the far right hand side called Data Analysis(this is located under the data tab). Picture:

Click it and a window should show up with all kind of options to select from scroll and select descriptive statistics then click ok. See picture:

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

Once you select descriptive statistics it will open a new window. In the first box select the data range that you want by clicking the cursor in the box then select the data. In the output box click a random empty cell on the page or below your data. Then check the box next to summary of statistics and click ok. See picture:

If you did everything correctly you should get an output looking like this:

 

[Chiller]

Re: Standard deviation the how to for the Cheap guys.

Very nice post.

And useful

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

The Data that was used was a string of 10 shots (175 SMK, Nosler Brass, Varget, CCI BR-2) coming from a Remington 5R using a Chrono F1. Note the SD of 6 FPS. I can show more examples on other software if people PM me. This may seem confusing and not worth all the fuss but if you are cheap like me then this is one way to get your SD. I also take my data book and transfer everything from into excel to see a long term results. Like graphing all groups from when I started with the rifle it will show accuracy spikes when I do upgrades or change powders kind of neat.

 

[bohem]

Re: Standard deviation the how to for the Cheap guys.

Nice post!

I have some thoughts on SD that were brought up by a long time scientist and shooter. I'll take them to a different thread for the sake of keeping this one succinct.

ETA: Here are some more thoughts on SD application

 

[Fred_C_Dobbs]

Re: Standard deviation the how to for the Cheap guys.

Wouldn't the truly cheap guys will be using (free) OpenOffice Calc instead of (Micro$oft) Excel?

 

[frankythefly]

Re: Standard deviation the how to for the Cheap guys.

Yeah you are right about the openoffice, almost everyone I know though gets office free or has access to it thats why I showed that example.
Also this data shows the variance and extreme spread not just SD. I am not saying that SD is the only way to go just giving you the tools to do it or check your chrono calcs.

 

[sobrbiker883]

Re: Standard deviation the how to for the Cheap guys.

Or you can click here:
http://easycalculation.com/statistics/standard-deviation.php