SMT Atterbury Test update

[Heman]

Made a mistake in what I was using to calculate the SD of the error. The SD is now the SD of the radial error. Will give you a better picture. The SD in general dropped .1" at 500 and 600, and dropped by about .2" for 300.

http://cihprs.wildapricot.org/resources/Documents/SMT accuracy update.pdf

Again this test was done during the match, and as stated once the Solo's sub millimeter algorithms are in the G2 it will be better.

Some of you may now decimate the results. Have fun................

 

[pat fulghum]

Just stating facts for you non-math majors out there.

You show a SD @300 yards as 0.17 inches.

What that SD means is...​

• 68.2% of the shots will fall within 1 SD or plus/minus .17" of the mean​
• 95% of the shots will fall within 2 SD, which is plus/minus .34 (2*.17) of the mean​
• 97% of the shots will fall within 3 SD, which is plus/minus .51" (3*.17) of the mean.​
• 3% of the shots will be have > .51" from the mean. ​
• In a 60 shot match, 1.8 shots will be "off" by at least 1/2" either for or against the shooter.​

The "X" ring is roughly 1.56" at 300 yards.

This is what SD means... You can have your own opinion how accurate that SD of .17 means (pun intended).​

 

[FatBoy]

does this mean .17" in one axis or two? I only understand SD when it comes to load testing, so I'm not sure how to take this.

If I understand it right, that means 97% of the shots may be marked on a circumfrancence from the actual shot, with a diameter of .51" in one direction or..

97% of my shots may fall onto a circumfrancence with a 1.2" diameter (+/- .51") or..

does it mean it can fall .51" on two axis, so maybe .25" high and .26" right? or some other variation of two distances making up .51"


or can it be all of these? or, am I totally wrong and still clueless?

 

[Keith Glasscock]

Since it appears to be the SD of the linear error, that could be any direction. So, based on what I see, the SD of the error could be best described as the radius of the circle in which a percentage of shots will be reported based on the circle's center being the actual point of impact.

Looking at the top column, it appears that there is an SD for each axis. I agree with Tom that the linear error is the most appropriate way to measure statistically.

Just a note for the non-math majors: Statistics are good predictors of generalized outcomes, and nothing more. Outliers happen...

Other than that, read what Pat wrote.

 

[HomeSlice]

Is the G2 upgrade a software change, hardware change, or both?

 

[HomeSlice]

.

View attachment 1047955

​

I understand a normal distribution, but what is the Y axis in this graph?

Edit: not a math guy

 

[pat fulghum]

@HomeSlice The Y axis is the percentage of the distribution.

Looking at the PDF... is says "In talking with Tom it was determined it was more accuarte to take the standard deviation of the radial error (Column J)."

Therefore the error is radial, meaning that 3% of the time the bullet's detection point will be outside a circle with a radius of .51" (diameter of 1.02") with the center of said circle at the true impact point.

That is how I interpret the reported results.

- pat

 

[Beau]

It means that in 80 shots, 21 of your shots will be marked about 1/3" from actual impact.

 

[243Mendoza]

Just stating facts for you non-math majors out there.

You show a SD @300 yards as 0.17 inches.

View attachment 1047955

What that SD means is...​

• 68.2% of the shots will fall within 1 SD or plus/minus .17" of the mean​
• 95% of the shots will fall within 2 SD, which is plus/minus .34 (2*.17) of the mean​
• 97% of the shots will fall within 3 SD, which is plus/minus .51" (3*.17) of the mean.​
• 3% of the shots will be have > .51" from the mean. ​
• In a 60 shot match, 1.8 shots will be "off" by at least 1/2" either for or against the shooter.​

The "X" ring is roughly 1.56" at 300 yards.

This is what SD means... You can have your own opinion how accurate that SD of .17 means (pun intended).​

That distribution has a mean of zero which is not the case for the SMT.