[R] round(1.5) = round(2.5) = 2?

From: Markus Didion <markus.didion_at_env.ethz.ch>
Date: Sun, 15 Jun 2008 11:26:18 +0200

Dear R-users

with a bit of grief I had to repeat an extensive analysis because I did not suspect (and therefore did not read the documentation) that round was implemented as "for rounding off a 5, the IEC 60559 standard is expected to be used, 'go to the even digit'", resulting in round(1.5) = 2
round (2.5) = 2.

As a non-mathematician I am both puzzled and intrigued by this rule as it is against what I have learned in my math courses, i.e. round(1.5) = 2
round (2.5) = 3.

I would like to understand the reason behind this rule.

Thanks for your comments.



Markus Didion

Waldkologie						Forest Ecology
Inst. f. Terrestrische Oekosysteme		Inst. of Terrestrial Ecosystems
Departement Umweltwissenschaften	Dept. of Environmental Sciences
Eidg. Technische Hochschule			Swiss Fed. Inst. of Technology
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