“Rounding to Even” for More Accuracy.

Round up for 5 or greater is a simple method that introduces a bias. See below to find out how to avoid the bias, as explained by the authoritative Math Forum.

There are two ways to round that are commonly taught. The rules we
give in most of our answers are those taught to children (and commonly used by computers), because they are simpler but are sufficient for
most purposes. Where statistics matter, and where numbers that END
with the 5 are common, rounding to even is preferred.
When an even decimal (or any even number) is followed by a 5, you
round down. When an odd decimal is followed by a 5, you round up.
For example: 75.45 = 75.4, but 75.55=75.6. Or rounding to the nearest
10, 145 = 140, but 155 = 160.

This type of rounding is also called “banker’s rounding.”  Microsoft Access uses banker’s rounding in its built-in “round ( )” command and Excel does not in its built-in “round( )” command, so you could have a case where you import data from Access and it changes slightly when it gets to Excel.  If you didn’t know what was going on, you would think it was a bug.


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