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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

I have revised the footnote "Why square the differences?" on the page Standard Deviation and Variance

Do you agree with the footnote?

Could it be better explained?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,920

Hi;

Those are all valid reasons. You could add that using the absolute value is harder to algebraically manipulate.

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,787

hi MathsIsFun,

That's pretty much what I say when I'm introducing this. It's interesting to watch a class would out the mean of the differences and then start scratching their heads. I think that practical drives the lesson home more effectively than anything and it improves their understanding of what a mean actually is.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,559

Thanks guys!

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 92,920

Hi;

Have you noticed that Wikipedia can save its pages in PDF format. So I save them and join them to make a nice book. Is that possible to make yours into PDF's?

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

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