阅读短文,从每题所给四个选项（A、B、C和D）中选出最佳选项。
Gao Xinyi, 14, No 1 Middle School Affliated in CCNU Chao Yang School, Beijing
I was once asked to give a speech in English in front of several native speakers at an organization last summer. I was asked to talk about my experience. At the beginning, I explained to the organizers that I was afraid to speak without preparation. But they told me that I had better get over it. When I first stood up in front of the crowd, my mind went completely blank. But then I began to talk about my story and used some gestures and facial expressions. Although I didn't speak very well, I still did it.
Ye Tong, 14, Hangzhou Entel Foreign Language School, Zhejiang
To be honest, I wasn't a brave girl. I still slept with my mother until I was a sixth-grader, because I didn't dare to sleep alone. Last year, one evening after I came back from school, my mom asked me to sleep in my own room. I thought I had grown up, so I should learn to be independent. Though I was frightened at first, I slept in my own room for the first time. I did it. I'm really proud of myself! This is the bravest thing I have ever done.
Zhang Yiyi, 14, Taiyuan Foreign Language School, Shanxi
I didn't dare to ride the roller coaster all the time. I thought it was a terrible thing. However, my friend asked me to try it when we were in Disneyland, in Hong Kong last year. I decided to take a try. It took off so fast. It was a cool feeling, like you were flying! That was extremely good fun. Someone once said, "Life is a roller coaster ride, tighten your seat belts, enjoy the journey, remember the up always has a down." That is right. I have fallen in love with the roller coaster.
，得到一组新数据，若求得的新数据的平均数是
，方差是
，则原来的数据的平均数和方差分别是( )