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Subject: Re: [office-comment] RSQ - Unstable Algorithm

• To: office-comment@lists.oasis-open.org
• Date: Fri, 06 Jul 2007 22:17:58 +0300

```Hello

I noticed that the algorithms used for the various OOo Calc functions
have been recently improved/corrected [including RSQ() ]. While I
sneaked through the code, it struck me the simplicity of the RSQ()
implementation.

Indeed, RSQ() is the *square of the Pearson coefficient*, so I wonder:
*Why does the OASIS document contain that awful formula  instead of the
straightforward one*?

I verified in the last hour that the 2 formulas are indeed
*mathematically identical*, so I am really puzzled. The square of the
Pearson coefficient is simply:
r^2 = { sum[(Xi - Xm)(Yi - Ym)] }^2  / {sum[(Xi - Xm)^2] * sum[(Yi -
Ym)^2] }

Indeed, just take the square of the Pearson coefficient!!!

[IF somebody is interested in the mathematical calculations, give me a
short notice, BUT I'll need a couple of days to type it on the computer.]

[The used formula did *MISLEAD* me, too. I thought it is some really
weird function.]

Is there any reason to use that complex and incomprehensible formula,
instead of the simple and straightforward one?

Sincerely,

Leonard
```

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