一道概率统计问题的纠错

• 作 者: 张光田
• 机 构: 山东省枣庄市第八中学,
• 出 处: 数学通讯
• 发表日期: 2009年Z2期
• 关键词: 概率统计 等可能事件 正四面体 参考资料 分点 分布列 随机变量 逆时针方向 条件概率

在很多参考资料上,有这样一道题目:把圆周分成四等份,A是其中一个分点,动点Q在四个分点上按逆时针方向前进.现投掷一个质地均匀的正四面体,它的四个面上分别写着1,2,3,4四个数字,Q从A点出发,按照正四面体面上的数字前进几个分点,转一周之前继续投掷.(1)求点Q恰好返回A点的概率;

In many references, there is a question that divides the circumference into four equal parts, where A is one of the points and point Q moves counterclockwise at the four points. Now throw a regular tetrahedron of uniform texture, On each of its four sides, there are four numbers, 1, 2, 3, and 4. Starting from point A, Q points forward by a few points on the face of a tetrahedron and continues to throw before turning on a week. Q exactly the probability of returning to point A;