章节大纲

  • 常规

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  • 计算具有同样可能性结果的简单事件概率

    In This Lesson
    ::在本课程中

    You  will explore more events with equally likely outcomes . This text is no longer going to refer to experimental probability . Anytime you see " probability ," it is referring to theoretical probability . 
    ::您将探索更多具有相同可能性结果的事件。 此文本将不再引用实验概率。 每当您看到“ 概率” 时, 它指的是理论概率 。

     

    Throwing Darts
    ::投投投投投投篮

    Below is a very basic dartboard, without a bullseye. There are 20 sections on the dartboard, and you have an equal likelihood of hitting any of them.  The  numbers around the circle represent the point values for each section if you are keeping score.
    ::下面是一个非常基本的飞镖板,没有公牛眼。在飞镖板上有20个区块,你可以打中其中任何一个区块。圆圈周围的数字代表每个区块的点值,如果你保持得分的话。

    • Find probabilities for different sets of numbers (numbers less than 8, multiples of 3, etc)  by clicking on the sections. The fraction will adjust accordingly.
      ::通过点击各节来查找不同数字组(数字小于8,乘以3,等)的概率。该分数将相应调整。
    • Find   sets of numbers   that  have  P = 0.2 . 
      ::查找有P=0.2的数组。

     

     

     

     

     

    It's in the Bag
    ::在包里,在包里

    Hoang has a bag of 16 marbles, with 4 of each color: red, blue, green, and black. Use the interactive to determine the probability of  getting a red marble out of the bag. Then determine if the probability of a red marble is different from the probabilities of other colors. 
    ::Hoang 有一袋16颗大理石, 每颗颜色有4颗: 红色、 蓝色、 绿色和黑色。 使用互动来确定从袋子中取出红大理石的可能性。 然后确定红大理石的概率是否与其他颜色的概率不同 。

    • Move one green, red, black and blue marble out of the bag to see how the probabilities change.
      ::将一个绿色、红色、黑色和蓝色的大理石从包中移开,看看概率是如何变化的。
    • The probabilities of  each color are shown to the right of the paper bag.
      ::纸袋右侧显示每种颜色的概率。

     

     

     

     

    Discussion Question
    ::讨论问题

    Why is the  likelihood of  picking a certain marble after a series of  marbles   different from the  likelihood  of picking  a  series of marbles and then  a certain marble ? 
    ::为什么在一系列大理石之后选择某种大理石的可能性不同于选择一系列大理石和某种大理石的可能性?

    Using probability to predict is a very important skill. As the number of marbles are pulled from the bag, the denominator decreases, thus changing the probability. If you had pulled three red marbles from the bag, the chance of pulling the fourth red marble from the bag would be 1 out of 13. So, it is far more likely to pick any other color. Notice, that the probability goes from being equally likely at the beginning of the event , to not equally likely once you start taking marbles out of the bag. 
    ::使用概率来预测是一个非常重要的技能。 当大理石从袋子中拉出时, 分母会下降, 从而改变概率。 如果您从袋子中拉出三个红大理石, 那么从袋子中拉出第四个红大理石的机会将是13分之一。 因此, 选择任何其他颜色的可能性要大得多。 请注意, 概率从事件发生之初的同样可能性, 到开始从袋子中取大理石时, 概率就不同了 。

       Summary
    ::摘要

    • Use probability models to help you determine probability of events.
      ::使用概率模型帮助您确定事件的概率 。
    • Use probability to predict the next event, but make sure you change the denominator and numerator accordingly.
      ::使用概率来预测下一个事件, 但确保您相应更改分母和分子 。