某省从3个水中氟含量不同的地区随机抽取10~12岁儿童,进行第一恒齿患龋率的调查,结果如下表:<img src='https://img2.soutiyun.com/shangxueba/ask/18174001-18177000/18175320/2015111609313625317.jpg' />

A. [’[’无效假设应为()。A.<img src='https://img2.soutiyun.com/shangxueba/ask/18174001-18177000/18175320/2015111609353833905.jpg' /> B.<img src='https://img2.soutiyun.com/shangxueba/ask/18174001-18177000/18175320/201511160935547883.jpg' /> C. P<sub>1</sub>=P<sub>2</sub>=P<sub>3</sub> D.<img src='https://img2.soutiyun.com/shangxueba/ask/18174001-18177000/18175320/2015111609362225245.jpg' /> E. 以上全不对

时间:2023-06-20 10:50:10

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