理论概率模型

播放段落

In This Lesson
::在本课程中

播放段落

Y ou will use the theoretical probability of certain events to determine the likelihood of certain outcomes .  
::您将使用某些事件的理论概率来确定某些结果的可能性。

播放段落

Probability is defined as  $\begin{array}{r}\frac{\text{number of favorable outcomes}}{\text{total number of outcomes}}\end{array}$
::概率的定义是:有利成果的数量

播放段落

The probability of an   event is written as $\begin{array}{r}P(A),\end{array}$  where $\begin{array}{r}P\end{array}$  represents probability and $\begin{array}{r}A\end{array}$  represents the event. For example, the equation  $\begin{array}{r}P(A)=0.4\end{array}$   means  "the probability of event $\begin{array}{r}A\end{array}$  is 40%." In an equation, $\begin{array}{r}P\end{array}$ is always written as a decimal between 0 and 1. A favorable outcome is an outcome that meets the criteria of the probability. For example, if you are finding the probability of rolling a six-sided number cube and want to find the probability of rolling an even number, the favorable outcomes would be 2, 4, and 6.
::事件概率以 P( A) 写成, P 代表概率, A 代表事件。 例如, 等式 P( A) =0. 4 表示“ 事件 A 概率为 40% ” 。 在 等式中, P 总是以小数小数写为 0 和 1 。 有利的结果是一个符合概率标准的结果。 例如, 如果您找到滚动一个六面数字立方体的概率, 并想要找到滚动一个偶数的概率, 则有利的结果将是 2 、 4 和 6 。

 

---

播放段落

Roll the Dice
::滚骰子

播放段落

Kelly decides that rather than rolling a die  hundreds of times to determine the likelihood of  a particular outcome, she will use what she knows about probability and  find the ratios of different outcomes based on the sides of the die.  
::Kelly决定,她将使用她所知道的概率,根据死亡的侧面找到不同结果的比率,而不是用数百次滚动死亡来确定特定结果的可能性。

 

 

 

 

 

 

 

 

 

 

 

 

播放段落

Do you think that experimental probability can be the same as theoretical? When and why?  
::你认为实验概率可以和理论一样吗?什么时候和为什么?

播放段落

In  the interactive, you  saw that if the number of trials in an experiment is very large (over 100), the experimental probability approaches the theoretical.
::在互动中,你看到,如果实验中的试验数量非常大(超过100),实验概率就会接近理论。

播放段落

Recall the formula for the theoretical probability:   $\begin{array}{r}\frac{\text{number of favorable outcomes}}{\text{total number of outcomes}}\end{array}$
::回顾理论概率的公式:有利结果的数量

播放段落

Moving forward , when you are asked to find the probability ,  assume you are finding the theoretical probability.
::向前推进,当被要求找到概率时,假设你正在找到理论概率。

 

---

播放段落

What's my Card?
::什么是我的名片吗?

播放段落

You have a standard deck of 52 cards.  This image below shows the results from a simulation for 500 picks, in which the card was put back each time.
::您有一个由 52 张牌组成的标准甲板。 下面的图像显示500个选牌的模拟结果, 这张牌每次都被放回去 。

播放段落

You want to compare the experimental probability from the data above to the theoretical. To determine theoretical probability, select the cards that you would like in the numerator, and the fraction will adjust accordingly.  
::您想要比较实验概率, 从上面的数据到理论。 要确定理论概率, 请在分子中选择您想要的牌, 分数会相应调整 。

 

 

 

 

 

 

 

 

 

 

 

 

播放段落

Discussion Question
::讨论问题

播放段落

Consider  the likelihood of drawing any one value  or face card over another  and the likelihood of drawing any suit over another. What do you notice?  
::考虑一个值或脸卡高于另一个值或面卡的可能性,以及任何西装高于另一个值或面卡的可能性。你注意到什么?