问题
单项选择题 A1型题
为了比较同一组儿童身高和体重两项指标的变异程度的大小，可选用的变异指标为（）
A．全距
B．标准差
C．方差
D．变异系数
E．四分位数间距
答案
参考答案：D
解析：五个选项都是表示变异程度的指标，其中选项D适用于比较不同组间观察指标的度量衡单位不相同，或虽单位相同但均数相差较大时的变异程度的比较。
搜题请搜索小程序“爱下问搜题”
为了比较同一组儿童身高和体重两项指标的变异程度的大小，可选用的变异指标为（）
A．全距
B．标准差
C．方差
D．变异系数
E．四分位数间距
参考答案：D
解析：五个选项都是表示变异程度的指标，其中选项D适用于比较不同组间观察指标的度量衡单位不相同，或虽单位相同但均数相差较大时的变异程度的比较。
| 完形填空。 | ||||
| I used to live selfishly, I should admit. But one moment changed me. I was on my lunch break and had 1 the office to get something to eat. On the way, I 2 a Busker (街头 艺人), with a hat in front of him. I had some 3 in my pocket, but I would not give them to him, thinking to myself he would 4 use the money to feed his addiction to drugs or alcohol. He 5 like that type-young and ragged. 6 what was I going to spend the money on? Only to feed my addiction to Coca-Cola or chocolate! I then 7 I had no right to place myself above 8 just because he was busking. I 9 and dropped all the coins into his 10 , and he smiled at me, I watched for a while. As 11 as it sounds, I expected something more to come from that moment-a feeling of 12 or satisfaction, for example. But nothing happened 13 , I walked off. "It proved to be a waste of 14 ," I thought. On my way home at the end of the 15 , I saw the busker again and he was 16 . I watched him pick up the hat and walk 17 a cafe counter. There he poured the 18 contents into a tin collecting 19 an earthquake fund- raising (募捐) event. He was busking for charity (慈善)! Now I donate any 20 I have to charity tins and enjoy the feeling of giving. | ||||
|