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Re: import data problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123261] Re: import data problem
  • From: DrMajorBob <btreat1 at austin.rr.com>
  • Date: Tue, 29 Nov 2011 07:06:19 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201111281054.FAA19786@smc.vnet.net>
  • Reply-to: drmajorbob at yahoo.com

x was Set equal to 20.05 somehow, so

LinearModelFit[data,{x, x^2, x]

came out as

LinearModelFit[data,{20.05, 402.003}, 20.05]

Notice that

20.05^2

402.003

Use Clear[x] or x = . before LinearModelFit.

Bobby

On Mon, 28 Nov 2011 04:54:29 -0600, Harry <hvdosten at gmail.com> wrote:

> Hi out there,
>
> I don't understad what happens with my data...
>
>
> There are 401 lines of input data). The last lines are:
>
> ...
>   19.7999992 -9.13599968
>   19.8500004 -11.6960001
>   19.8999996 -11.9519997
>   19.9500008 -12.2080002
>   20. -12.9759998
>
>
> Importing these data in Mathematica via
>
> data = Import["00000.dat", "Table"]
>
> and everything seems to be ok. But if I try this:
>
> y = LinearModelFit[data, {x, x^2}, x]
>
>
> there is the error message: LinearModelFit::ivar: "{20.05} is not a
> valid variable"
>
> and the output is printed as:
>
> ...
> {19.85, -11.696}, {19.9, -11.952}, {19.95, -12.208}, {20., -12.976}},
> {20.05, 402.003}, 20.05]
>
>
> Why are the data extended to {20.05, 402.003}, 20.05]?
>
> Thanks a lot for your hint. I hope that this question ist not too
> stupid, but I feel I am standing in front of a wall and don't know how
> to overcome this...
>
> Thanks a lot.
>
> Harald
>
>
>
>
>


-- 
DrMajorBob at yahoo.com



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