This paper explains a correction to the rounding rule previously publishedin this Journal. The earlier article reported that the best way to roundnumbers is to always round up when the first digit dropped is 5. However,this will lead to accumulation of error when errors are averaged. Arounding strategy that leads to less error is to round up when 5 isfollowed by any nonzero digits, but to round even when 5 is followed byzeros or no other digits. By rounding the last kept digit to an evennumber, half the time the digit is increased and half the time it is keptthe same so that errors tend to cancel when averaged.
Midden, W. Robert, "Rounding Numbers: Why The ''new System'' Doesn't Work" (1997). Chemistry Faculty Publications. 94.
Journal Of Chemical Education