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在高三复习时 ,笔者的一个学生S1 做了这样一道习题 :对汽车经过某一段公路的时速进行调查 ,在所得的频率分布直方图中 ,与时速 6 0～ 6 5(km)对应的长方形面积为 0 .0 9,则从 10 0辆经过该公路的汽车中任取 2辆 ,时速为 6 0～ 6 5(km)的概率为?S1 的答案是 0 .0 0 81,与参考答
During the third year of the review, a student S1 of the author did the exercise to investigate the speed of a car passing through a certain section of road. In the resulting frequency distribution histogram, the rectangular area corresponding to the speed of 60 to 65 square kilometers (km) For a 0.09, then two of the vehicles that pass through the highway are taken from the 100 vehicles. The probability of a speed of 60 to 65 (km) is ? 0. The answer to S1 is 0. 0 0 81.