当抽样单位数增加3倍时，随机重复抽样平均误差比原来（）。[首经贸2007研]

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SQL Error: select id,body,options from ***_enewstiku where sourceid='30462' and id < 2461245 and id<>'2461245' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='30462' and id > 2461245 and id<>'2461245' order by id asc limit 5