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Standard Deviation of Velocity Spread
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...SD is useful for estimating the distribution of the population. The fact the ES in your first data set was 22 does not mean that load would never deviate more than 11 fps from the mean; the 99.7% confidence level generated by the SD practically guarantees that the true ES for the expected population was greater than 22, and you proved that when you shot ten more times.


I made up the data sets. The numbers do not represent actual measured velocities, just numbers from my imagination.

I did this to make a point about numbers and the definitions of SD and ES.

No where did I say the numbers represented fps.

AAZW, you made that false assumption...wrong again.

Do you really believe that by "shooting more", a real shooter would reproduce exactly nine of the velocities in perfect sequence, that is...

3000,3010,2990,3005,2995,2993,3003,3007,2997,3012,...and then followed in perfect sequence by...

3000,3010,2990,3005,2995,2993,3003,3007,2997, and then conveniently 3032.

Really? You thought these data sets represented actual measured velocities.

The odds of these data sets representing true velocity data sets are one in a gazillion.

PM me, I have a bridge to sell you.

ES does not define SD, although they can correlate.

SD needs to be calculated; and, of coarse "SD is useful for estimating the distribution of the population..." This is why SD is used. ES, by itself, is not enough.

Do you have something valuable to add to the discussion?
 
Posts: 3720 | Registered: 03 March 2005Reply With QuoteReport This Post
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You are right, I did not study the sequence of numbers.

However, nothing I said in my discussion of statistics is untrue. If you shoot more, you have a better estimate of the entire population set. Even though you made up the numbers, the SD in your first ten "shots" implied the true ES of the entire population was higher than 22 - That is my contribution to the discussion but if you prefer I butt out, I would be happy to do so.

Have a nice day; I have a software company to run.


Don't Ever Book a Hunt with Jeff Blair
http://forums.accuratereloadin...821061151#2821061151

 
Posts: 7570 | Location: Arizona and off grid in CO | Registered: 28 July 2004Reply With QuoteReport This Post
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