在选择数据的访问路径时,如果没有正确的列分布统计数据,DB 2可能没有足够的信息来做出最佳的选择,尤其是如果数据出现严重误差。
Without correct column distribution statistics, DB2 may not have enough information to make the best choice when choosing an access path to the data-especially if data is heavily skewed.
叙述了液柱式压力计的精度,对U形管压力计和双管差压计的正确使用方法及误差修正做了简要分析。
The precision of liquid column manometer was described. The correct use method and error correction of U tube manometer and double tube differential pressure gauge were analysed.
通过加工实验,验证了三种刀位计算方法的有效性和误差分析方法的正确性。
The validity of three methods and the correctness of the error calculation were proved in the machining experiments.
Again, you can't even correct for it because, let's just say, the whole population overestimated calories and things were underestimated by 30% percent, well then you just put in that correction and you know what you got.
你甚至无法纠正这个误差,因为,比方说,整个总体人群都高估了卡路里,或者都低估了30%的卡路里,研究人员纠正误差才能得到正确数据
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