决定t分布位置的是（） A.总体均数 B.总体标准差 C.标准误 D.自由度 E.以 发布时间：2017-05-06 15:44 │ 来源：www.tikuol.com 题型：单项选择题 A1型题 问题： 决定t分布位置的是（）A.总体均数B.总体标准差C.标准误D.自由度E.以上都不是
题型：单项选择题 A1型题 任务型阅读。 下面一篇短文是电视台的《健康报道》节目介绍流行性感冒的录音稿，为了使人们更容易了解流感，请你仔细阅读，并设计一个说明情况的表格，表达下面文章内容。现在表格已经基本设计好，请你在空白处填上适当的单词，每个空格不得超过4个词。 It's nine o'clock, time for Health Report. There has not been a worldwide spread (传播) of flu (流行性感冒) since 1968. Experts say there should have been another by now. The so-called Spanish flu in 1918 became the most deadly flu ever recorded. It killed an estimated twentymillion to fifty million people. Almost half were young adults. There were two other widespread flu in the twentieth century. The Asian flu struck in 1957, and the HongKong flu in 1968. Scientists at the United States Centers for Disease Control and Prevention say the cause of the widespreadSpanish flu is not clear. But the two others are known to have resulted from a human virus that became mixedwith a bird flu virus. And that could happen again. Scientists first identified bird flu in Italy more than one hundred years ago. Bird flu is caused by type A fluviruses. Type A are the most common, and usually cause the most serious flu spread in people. Currently themost serious kind of bird flu is known as h-five-n-one. It has spread among chickens and ducks in Asia. Number of worldwide flu in 20th century1. Cause of Spanish flu2. Cause of Hong Kong flu3. A human virus mixed with Places where bird flu often outbreaks 4. countriesMost serious kind of bird flu 5. 查看答案