Question

若一組數(shù)據(jù)2、-1、0、-3、5、x的平均數(shù)為1，則這組數(shù)據(jù)的中位數(shù)為    ．

Answer 1

【答案】分析：先根據(jù)平均數(shù)的定義求x，再求中位數(shù)．
解答：解：若一組數(shù)據(jù)2、-1、0、-3、5、x的平均數(shù)為1，則有（2-1+0-3+5+x）=1，則x=3．
將該組數(shù)據(jù)按從小到大的順序排列，-3，-1，0，2，3，5．
數(shù)據(jù)個數(shù)為偶數(shù)，則最中間的兩個數(shù)的算術(shù)平均數(shù)即為這組數(shù)據(jù)的中位數(shù)，即中位數(shù)是1．
故填1．
點評：本題考查了平均數(shù)和中位數(shù)的定義．一組數(shù)據(jù)的中位數(shù)與這組數(shù)據(jù)的排序及數(shù)據(jù)個數(shù)有關(guān)，因此求一組數(shù)據(jù)的中位數(shù)時，先將該組數(shù)據(jù)按從小到大（或按從大到�。┑捻樞蚺帕校�然后根據(jù)數(shù)據(jù)的個數(shù)確定中位數(shù)：當(dāng)數(shù)據(jù)個數(shù)為奇數(shù)時，則中間的一個數(shù)即為這組數(shù)據(jù)的中位數(shù)；當(dāng)數(shù)據(jù)個數(shù)為偶數(shù)時，則最中間的兩個數(shù)的算術(shù)平均數(shù)即為這組數(shù)據(jù)的中位數(shù)．平均數(shù)的求法，．