If you just want to make it short: 

perl -ane'$t{$F[0]}+=$F[1];$c{$F[0]}++}{printf"$_ %.3f\n",$t{$_}/$c{$_
+}for+sort+keys%t'

[download]

In reply to Re^2: HOW to calculate the column data by jwkrahn
in thread HOW to calculate the column data by xbmy

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