Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: please solve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg52998] Re: please solve
  • From: rcmcll at yahoo.com
  • Date: Sun, 19 Dec 2004 06:14:43 -0500 (EST)
  • References: <cprk0m$r87$1@smc.vnet.net><cpuh1i$gui$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Maybe I should define t. t is just time 1,2,3..,n and t^2 is
1,4,9,...n^2 like that.
I didn't think about singularity as this is a simple regression problem
that works when one uses actual values. I'm trying to get simple
formulas for beta instead of the usual ones.Sorry about that. Maybe I
can take usual formulas and try to get a simple solution thru that.
Thanks for all the effort
Bob

Robert M. Mazo wrote:
> On Thu, 16 Dec 2004 09:20:22 +0000 (UTC), rcmcll at yahoo.com wrote:
>
> >Greetings:
> >
> >Could someone please solve this symbolically?
> >This is just the ols formula for beta-hat but I need a symbolic
> >solution for this special case.
> >
> >b = inv(x'x)x'y
> >
> >where
> >
> >x =  1  t  t^2
> >1  t  t^2
> >1  t  t^2
> >
> >
> >and simplify simplify simplify!!
> >
> >Thanks,
> >
> >Bob
>
> If I understand the notation, x is a matrix.  Yes?  If so, x is
> singular and doesn't have an inverse.  Hence neither does x'x, so the
> problem has no solution.  Or, better put, the problem is ill posed.
> 
> A dsifferent Bob


  • Prev by Date: Re: File association in 5.01
  • Next by Date: Re: Mathematica language issues
  • Previous by thread: Re: please solve
  • Next by thread: Re: Re: please solve