航模小组用八架飞机作飞行试验，各架飞机飞行的时间如下表．
（2）用哪个数据代表八架飞机的飞行时间比较合适？ （3）如果A飞机不飞，那么其余七架飞机飞行时间的平均数是多少？用它来代表这些飞机的飞行试验水平可以吗？ |
（1）（8+18+14+26+29+27+23+31）÷8
=176÷8
=22（秒）；
把这组数据从大到小排列如下：
31、29、27、26、23、14、18、8，
（26+23）÷2
=49÷2
=24.5．
答：八架飞机飞行时间是22秒；中位数是24.5．
（2）答：用中位数代表八架飞机的飞行时间比较合适，它不受较大或较小数据的影响．
（3））（18+14+26+29+27+23+31）÷7
=168÷7
=24（秒）
答：如果A飞机不飞，那么其余七架飞机的平均飞行时间是24秒；用它来代表这些飞机的飞行试验水平可以．
Joshua, my son, is fifteen years old. He was born with Down Syndrome (唐氏综合症). In the last fifteen years. I have experienced many difficult and stories. However, right now I want to just stick to the topic of . When Joshua was born, the doctor us not to “waste our time, energy or money". They claimed that our son would never accomplish anything. They told us he would never walk, talk or learn to use the toilet. , we were not about to accept the words. However, we weren’t really sure what to expect. Therefore, we expected him to develop at his own pace, with a lot of help and encouragement, but only to develop little. We decided that we saw progress we could never give up. Very early on, we knew in our hearts that we had to have high expectations, but how high? We could not set goals for him that he could not ever possibly reach. , if we did not have high hopes, the chances would be very slim for him to work to his potential. When Joshua was four and a half years old, his younger sister, CJ, was three and attended the same preschool in a younger class. The school an art contest and all the children in it presented pictures. The pictures were hung on the wall and the president of the local church, who was not personally with the children, was appointed to be the . On the day of the contest, I made my through the crowded parents to see Cf’s picture, it was likely to be hung there, but Joshua's class pictures were not yet up and I didn’t think twice about seeing his picture leaving the building. You see, I had no expectation that Joshua would win; it was for me to know that he was able to draw a picture and have it with those of the other children. Well, when I returned to the kids, you can image my when I discovered that Joshua was the winner from his class! Proud and excited, he told everyone, “I won the contest! I it! ” CJ kept insisting that she had won too and it was certainly a feeling to know that Joshua had achieved something that his sister had not. After that I decided to keep my expectations . It seems that most people work to whatever expectations are set for them. Why should Joshua be any ?
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