(2005•臺州)現(xiàn)有7名同學測得某大廈的高度如下:(單位:m)
29.8 30.0 30.0 30.0 30.2 44.0 30.0
(1)在這組數(shù)據(jù)中,中位數(shù)是______,眾數(shù)是______,平均數(shù)是______;
(2)憑經(jīng)驗,你覺得此大廈大概有多高?請簡要說明理由.
【答案】
分析:(1)根據(jù)中位數(shù)、眾數(shù)、平均數(shù)的概念,求出這組數(shù)據(jù)的中位數(shù)、眾數(shù)、平均數(shù);
(2)憑經(jīng)驗,大廈高約30.0m.數(shù)據(jù)44.0誤差太大,或測量錯誤不可信.
解答:解:(1)在這組數(shù)據(jù)中,將這組數(shù)據(jù)按從小到大排列為,由于有奇數(shù)個數(shù),最中間的數(shù)是30.0,則中位數(shù)為30.0;
因為30.0出現(xiàn)的次數(shù)最多,則該組數(shù)據(jù)的眾數(shù)為30.0;
平均數(shù)是
![](http://thumb.zyjl.cn/pic6/res/czsx/web/STSource/20131019110040516872152/SYS201310191100405168721022_DA/0.png)
=32.0.
(2)憑經(jīng)驗,大廈高約30.0m.數(shù)據(jù)44.0誤差太大.
點評:本題考查平均數(shù)、眾數(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,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�。┑捻樞蚺帕校缓蟾鶕�(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).