T'ai Chi : Some math/stat questions for you

[69dodge]

Originally posted by T'ai Chi
Well, that can be disproved by finding one counter-example where range/SD < 2.

data = {2,4}
The range = 2, and the SD = sqrt(2), so

the range/SD = sqrt(2) < 2.

If you're still using the sample standard deviation (with a denominator of n - 1), then this is a counterexample. Your attempted proof uses the population standard deviation (with a denominator of n), though, so I thought you changed your mind about that.

 

[T'ai Chi]

If you're still using the sample standard deviation (with a denominator of n - 1), then this is a counterexample. Your attempted proof uses the population standard deviation (with a denominator of n), though, so I thought you changed your mind about that.

I got no clue now.

I think I'll stick to the sample standard deviation, but I'm pretty sure (at least I have this in my notes) that the inequality holds in any case. (of course if it holds in the n-1 case it holds in the n case)