以下数据，最接近一间普通教室的天花板距该教室地面的高度的是  （     　）

中世纪的欧洲，德国皇帝亨利四世在冰天雪地里站在教皇的门前乞求宽恕，这反映了

      Ann is   1  American worker. She works2a big factory(工厂) in America. It's 3in the morning. Ann 4 up. She is sitting on the bed. She is putting  5her clothes. She  6nothing to do today.
     Now Ann  7  at the table. She is    8 her breakfast. There is a cup of orange and some bread on the table. Ann is  9  the orange and eating the bread. She is  10today's newspaper.

统计得到的一组数据有80个，其中最大值为154，最小值为50，取组距为10，则可将这组数据分为____ 组．