题目

How to Calm Your Teen's Nerves before an Exam Stress is a feeling of physical and mental of emotional strain of tension, which disturbs or interferes with normal physiological balance. Stress can be overwhelming for anyone, but it can be especially difficult for a teen that has not yet developed effective coping skills. A major source of teen stress is school exams, and test anxiety is not uncommon. So, how can parents help their teen stay calm before an exam?     Recognize when your teen is under stress.     Teens can feel an immense pressure to do well on exams. For some teens, 某校抽检60个学生的体重如下（单位：kg）38  32  39  40  35  45  37  38  40  2939  41  37  42  39  34  36  39  42  3644  33  29  40  35  39  37  46  39  3139  36  42  38  41  36  44  34  38  3841  39  39  34  36  48  30  39  37  4242  45  34  48  43  35  39  44  43  44（1）填写频数分布表： 分组 28.5～33.5 33.5～38.5 38.5～43.5 43.5～48.5 频数记录         频数        （2）根据上表绘制频数分布直方图．