问题 多项选择题

对于一元线性回归分析来说()

A.两变量之间必须明确哪个是自变量,哪个是因变量

B.回归方程是据以利用自变量的给定值来估计和预测因变量的平均可能值

C.可能存在着y依x和x依y的两个回归方程

D.回归系数只有正号

E.确定回归方程时,尽管两个变量也都是随机的,但要求自变量是给定的

答案

参考答案:A, B, C, E

单项选择题 B1型题
阅读理解

     Loma just had to get in touch with someone: "I had to tell my best friend something important. I tried

calling her but I couldn't get through. So I sent her an e-mail and then I spoke to her on MSN. Without

technology I would not have been able to tell her. "

     Staying connected with friends and family is important for us. That's why we asked our readers to tell

us how cell-phones, e-mail, blogs, text messaging, and personal pages help them keep in touch. More

than 1,500 responded.

     Most of them told us they couldn't live without technology: 80%of teens said they need technology to

stay in touch. Almost 30%said they'd be completely out of their friends without their cell-phones and

other methods of communication.

     What do they do when they've got news they need to share now? Most teens say they try to reach

their friends by phone. But if they don't reach them, they use QQ, e-mails, and text messaging to get the

words out.

     Lots of people use one way of communication-like text messaging-to get a friend's attention and then

use another where they can talk more. "My friends and I always tell each other everything that happens.

So I send them text messages to tell them to come online so we can talk about it," said Sabeiha.

     "When planning to get together with friends", Julian said, "the easiest and fastest way I know is to

send a text message to my contact group." Jocelyn said. "If I want to go to see a movie with a few

friends, I usually send text message to them. By telephone, you have to call every single friend one by

one. But text messaging allows you to send the same message to as many as you'd like, which saves a lot

of time."

1. Which of the following is NOT mentioned in the passage?

A. E-mails.    

B. Blogs.        

C. Personal pages.    

D. Personal letters. 

2. What do most young people use first when they have news to tell their friends?

A. MSN.      

B. QQ.            

C. Phones.          

D. Text message.

3. The underlined part "get the words out" means"      ".

A. send the message              

B. send the e-mail

C. talk with their friends            

D. meet their friends

4. In which part of a newspaper can you find this passage?

A. Sport.      

B. Education.    

C. Technology.      

D. Culture.