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WalterSchrabmai12-Amethyst
12-Amethyst
June 3, 2016
Question

confidence function in Mathcad vs. manual calculation

  • June 3, 2016
  • 1 reply
  • 11816 views

Hi friends,

I really can not find the error, why the manual calculation of the std errors of the parameters are completely wrong compared with confidence function.

Can anyone help, please?

Walter

1 reply

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WalterSchrabmai12-AmethystAuthor
12-Amethyst
June 3, 2016

I found it: Ks and Kp was changed in the Model definition. and of course I must fit the function before. sorry

W
WalterSchrabmai12-AmethystAuthor
12-Amethyst
June 3, 2016

No!! I can not find the error in my sheet. Please help.

manu_wrong.gif

Here confidence.

auto_right.gif

R
RichardJ19-Tanzanite
19-Tanzanite
June 3, 2016

Your Covar matrix is wrong. The elements on the diagonals are variances. Since the variance is the square of the standard deviation it should never be negative.

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