POV-Ray : Newsgroups : povray.off-topic : Even more statistics : Even more statistics Server Time
29 Jul 2024 16:26:37 EDT (-0400)
  Even more statistics  
From: Invisible
Date: 5 Jul 2011 06:48:19
Message: <4e12ebf3$1@news.povray.org>
Suppose you have 1,000 numbers chosen at random with a uniform 
distribution [-1, +1]. Now suppose you take the discrete Fourier 
transform of this sequence of numbers. Since the input is random, the 
output is also random. But what distribution does it follow?

I've searched all over the Internet, and I can't seem to find the answer 
to this trivial question.

My best guess is that the Central Limit Theorem would apply, resulting 
in both the sine and cosine coefficients being normally distributed. 
(But with what parameters?) The CLT definitely applies to independent 
/identically distributed/ random variables. I'm fuzzy about what happens 
when the variables are not identically distributed, however. In this 
case, each variable follows a uniform distribution with the same 
midpoint, but the width of the distribution varies for each variable.

My simulation results seem to indicate a normal distribution also. But 
that doesn't really mean anything; there could just be a bug in my 
program which causes it to spit out dud data. Or perhaps the 
distribution /looks/ normal but is actually subtly different.


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