在廈門園博園草莓采摘園,五位游客每人各采摘了一箱草莓,草莓質量分別為(單位:千克):5,2,3,5,5,則這組數(shù)據(jù)的平均數(shù)和中位數(shù)分別是 .
【答案】
分析:先把數(shù)據(jù)按大小排列,再根據(jù)平均數(shù)和中位數(shù)的定義求解.中位數(shù)是第3個數(shù).
解答:解:這組數(shù)據(jù)5,2,3,5,5的平均數(shù)為

(5+2+3+5+5)=4;
求中位數(shù)時,先將該組數(shù)據(jù)按從小到大的順序排列為2,3,5,5,5.中間的一個數(shù)即為這組數(shù)據(jù)的中位數(shù),故這組數(shù)據(jù)的中位數(shù)是5.
故答案為4和5.
點評:本題考查平均數(shù)和中位數(shù).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,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,然后根據(jù)數(shù)據(jù)的個數(shù)確定中位數(shù):當數(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);當數(shù)據(jù)個數(shù)為偶數(shù)時,則最中間的兩個數(shù)的算術平均數(shù)即為這組數(shù)據(jù)的中位數(shù).平均數(shù)的求法,

.