变量数列分析的原则。
参考答案:
①要注意总体单位的同质性;
②用组平均数补充总平均数;
③用次数分布补充总平均数;
④集中趋势与离散趋势测度相结合;
⑤注意一般与个别相结合。
根据括号中所给的汉语写出单词,使句子意思完整正确。
1. These years it seldom snows in _____ (冬季) in Nanjing.
2. Don't always make your parents do this or that. Nick.You can do it _____ (自己).
3. Susan usually has some pieces of ______ (面包) and a bottle of milk for breakfast.
4. John is ______ (幸运的) enough to be chosen for the school football team.
5. If we don't protect the animals, We will be _______ (不能) to see them in the future.
嗅觉适宜刺激必须具有挥发性,是因为( )。
A.具有挥发性的物质才能作用于鼻腔上膜的嗅觉感受器B.具有挥发性的物质才能作用于鼻腔下膜的嗅觉感受器C.具有挥发性的物质才能作用于毛细胞D.具有挥发性的物质才能作用于科蒂氏器官