题目内容:
根据身高对l00个学生进行分组,l50~160cm的有l0个,组中值为l55;160~170cm的有70个.组中值为l65;170~180cm的有20个,组中值为l75,则加权算术平均数为( )cm。
A.155 A.155
A.155
A.155
B.175
B.175
B.175
B.175
C.165
C.165
C.165
C.165
D.166
D.166
D.166
D.166
参考答案:
答案解析: