MaplePrimes - answers and comments on Question, Mean-Absolute Deviation

Just one little note.

Jarekkk — Tue, 03 Jan 2012 21:16:40 Z

I think that sum(x[i](r[i,t]-u[i]))*sum(x[j](r[j,t]-u[j])) = w[t]^2 is OK, since i,j are independent, so you can rewrite it (use i instead of j) as sum(x[i](r[i,t]-u[i]))*sum(x[i](r[i,t]-u[i])) = w[t]^2.

hummm I am not sure they are independent

alex_01 — Tue, 10 Jan 2012 21:15:17 Z

hummm I am not sure they are independent though, I might be wrong.
It would be nice to prove that with maple...

What exactly should be shown?

Jarekkk — Thu, 09 Feb 2012 20:33:48 Z

@alex_01 I'm sorry I just noticed that you replied (a month ago). If it is still of interest for you, tell me, please, what exactly is unclear.

Are you familiar with this?

If so, then the problem is in this equality?

Both can be shown with mathematical induction.