问题 单项选择题

(三)某企业利用直方图对某零件外径尺寸进行控制。质检人员抽检了100个样本,绘制了频数分布表。表中显示,频数最多的组的中心值a一28,组距h=3,经计算∑f,u.-8,∑f.u.-300.(式中:f.表示第i组的频数m表示第i组的代表值)  根据上述资料,回答下列问题:

分布的标准偏差s为( )。

A.5.08

B.5.10

C.5.19

D.5.24

答案

参考答案:C

多项选择题
阅读理解

One day when Jack was walking in the park, he saw a woman, who lived a few miles away, sitting on a bench with a dog beside her. The dog was looking up at the woman.

Jack walked up to the woman and said, "Hello, Sue, how are you? May I sit and talk with you for a while?" "Of course, please sit down," Sue said. Jack sat down next to Sue on the bench, and they talked quietly together. The dog continued to look up at Sue, as if waiting to be fed.

"That's a nice dog, isn't he?" Jack said, pointing at the animal.

"Yes, he is. He's handsome. He's a bit of a mixture, but that's not a bad thing. He's strong and healthy."

"And hungry, "Jack said." He hasn't taken his eyes off you. He thinks you've got some food for him."

"That's true, "Sue said." But I haven't."

They both laughed and then Jack said, "Does your dog bite?"

"No, "Sue said, "He's never bitten anyone. He's always gentle and friendly."

Hearing this, Jack decided to hold out his hand and touched the animal's head. Suddenly it jumped up and bit him.

"Hey!" Jack shouted." You said your dog didn't bite."

Sue replied in surprise, "Yeah, I did. But this is not my dog. My dog's at home."

小题1:The dog looked at the woman because ___.

A.the woman wanted to feed him

B.the woman was friendly

C.he was strong and healthy

D.he was hungry小题2:Jack touched the dog because he believed ___.

A.the dog was handsome

B.Sue's dog was unfriendly

C.the dog belonged to Sue

D.Sue's dog was at home小题3:We can infer form the passage that ___.

A.Sue gave a wrong answer

B.Jack made a mistake

C.the dog wasn't dangerous

D.both Jack and Sue liked the dog小题4:Which of the Following can be the best title of the passage?

A.A Wrong Question

B.Sue's Dog

C.A pleasant Meeting

D.Sue's Friend