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import data problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123239] import data problem
  • From: Harry <hvdosten at gmail.com>
  • Date: Mon, 28 Nov 2011 05:54:29 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com

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







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