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**John E. Franklin****Member**- Registered: 2005-08-29
- Posts: 3,562

In "recent additions", I read about "rounding numbers".

The only word I would change is the one that says,

"it is all about **fairness**", when talking about why

the digit 5 is rounded up. I think it would be more

fair to say it is typically agreed upon that 5 should

round up. There are some times when 5 may round

down, but this is not the normal way to do it.

Finally, 5 is exactly halfway, so there is no fairness.

Teams with an unfair zero on a team is not fair.

Sorry we already talked about this before, but I couldn't resist mentioning it again.

**igloo** **myrtilles** **fourmis**

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,552

Yes, I need to write a much lengthier article about methods of rounding. Floor, ceiling, rounding 5 up on even or odd, etc.

It really is about "horses for courses", but the "5 up" method is simply the most common and agreed-upon method.

I guess you really need to think about your data before you decide what method to use.

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

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**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,306

0.0 0.1 0.2 0.3 0.4 5 numbers

0.5 0.6 0.7 0.8 0.9 5 numbers

fair

0.00 0.01 ... 0.49 50 numbers

0.50 0.51 ... 0.99 50 numbers

fair

0.000 0.001 ... 0.499 500 numbers

0.500 0.501 ... 0.999 500 numbers

fair

so the rounding can be inferred (imagined) as fair.

when talking about infinity, you can only infer and define.

**X'(y-Xβ)=0**

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**Ricky****Moderator**- Registered: 2005-12-04
- Posts: 3,791

I guess you really need to think about your data before you decide what method to use.

That could be a very large pitfall though because people can choose their rounding method to make their data fit better. Although in most cases it's not going to make a big difference.

George, I agree. The one thing people say is that you aren't rounding .0, and thus, it doesn't count. I can't understand why though.

"In the real world, this would be a problem. But in mathematics, we can just define a place where this problem doesn't exist. So we'll go ahead and do that now..."

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