happyjyl
第1楼2007/01/29
There are three general rules for rounding:
Rule 1- if the remainder beyond the last digit to be reported is less than 5, drop the last digit. Rounding to one decimal place, the number 5.3467 becomes 5.3.
Rule 2-if the remainder is greater than 5, increase the final digit by 1. The number 5.798 becomes 5.8 if rounding to 1 digit.
Rule 3- To prevent rounding bias, if the remainder is exactly 5, then round the last digit to the closest even number.Thus the number 3.55 (rounded to 1 digit) would be 3.6 (rounding up) and the number 6.450 would round to 6.4 (rounding down)if rounding to 1 decimal.
See page 12 in Hurlburt, R. (1994) Comprehending Behavioral Statistics, Brooks/Cole, Pacific Grove, CA.
happyjyl
第2楼2007/01/29
To replace a number having a given number of digits with a number (called the rounded number) having a smaller number of digits, one may follow these rules:
If the digits to be discarded begin with a digit less than 5, the digit preceding the 5 is not changed.
Example: 6.974 951 5 rounded to 3 digits is 6.97
If the digits to be discarded begin with a 5 and at least one of the following digits is greater than 0, the digit preceding the 5 is increased by 1.
Examples: 6.974 951 5 rounded to 2 digits is 7.0
6.974 951 5 rounded to 5 digits is 6.9750
If the digits to be discarded begin with a 5 and all of the following digits are 0, the digit preceding the 5 is unchanged if it is even and increased by 1 if it is odd. (Note that this means that the final digit is always even.)
Examples: 6.974 951 5 rounded to 7 digits is 6.974 952
6.974 950 5 rounded to 7 digits is 6.974 950.
何当奇
第3楼2007/01/29
四舍五入留双 round-to-even
The Round function utilizes round-to-even logic. If the expression that you are rounding ends with a 5, the Round function will round the expression so that the last digit is an even number. For example:
Round (12.55, 1) would return 12.6 (rounds up)
Round (12.65, 1) would return 12.6 (rounds down)
Round (12.75, 1) would return 12.8 (rounds up)
In these cases, the last digit after rounding is always an even number. So, be sure to only use the Round function if this is your desired result.
poorlittle
第5楼2007/01/31
“留双” may be translated as “rounding to an even value” (quoted from BS1957).
"舍" – round down
"入" – round up
"四舍六入" is a general speaking; it is a good reminder but not precise. 4.9999 also舍, 5.0001 also入
It is difficult to translate "四舍六入五留双". Perhaps, it may be translated as:
Round up when larger than 5
Round down when less than 5
Round to an even value when exactly 5
Regarding相关阐述"四舍六入五留双"是如何操作的英文文献, page 10 and 11 of British Standard BS1957 “The Presentation of Numerical Values” may be referred. (file has been uploaded above)
Both GB8170 and BS1957 recommend rounding to an even value. GB8170 is rather concise while BS1957 is more detailed and with explanation, for example, the Notes 2 on page 11 explains why rounding to an even value, not an odd value.
BS1957 is a national standard, therefore the wording used was in compliance with some rules to ensure the clauses to be precise and logical, and consequently it is difficult to understand.
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