连续两次正面朝上的预期翻转次数是多少？

概率是结果发生的可能性。事件的概率仅在 0 和 1 之间，并且也以百分比形式表示。事件 A 的概率通常写为 P(A)。

每当我们不确定事件的结果时，我们就会使用某些结果的概率——它们发生的可能性有多大。对这些概率的分析称为统计。为了理解概率，我们举一个抛硬币的例子：

有两种可能的结果——正面或反面。

硬币落在反面的概率是多少？您可能直观地知道可能性是一半/一半或 50%。

概率公式

$Probability \space of\space an\space event = \frac{Number\space of\space ways\space it\space can\space occur}{Total\space number\space of\space outcomes}$

$P(A) = \frac{Number\space of\space ways\space A\space occurs}{Total\space number\space of\space outcomes}$

活动类型

同样可能的事件

具有相同理论发生概率的事件称为等可能事件。同等可能的事件发生的概率相同。例如，如果我们掷骰子，那么得到 2 的概率是 1/6。类似地，从 1、2、3、4、5 和 6 中获得数字的概率是 1/6。

补充活动

只有两种结果的可能性表明事件将发生与否。就像一个人去或不去办公室，搭车或不搭车等都是互补事件的例子。基本上，事件发生的补充与它不发生的概率完全相反。

连续两次正面朝上的预期翻转次数是多少？

解决方案：

Probability of an event = (number of favorable event) / (total number of event).

P(B) = (Event B) / (total number of event).

Probability of getting a Head = 1/2.

Tossing a coin is an independent event, it is not dependent on how many times it’s been tossed.

Probability of getting 2 heads in a row = probability of getting head first time×probability of getting head second time.

Probability of getting 2 heads in a row  = (1/2) × (1/2) = 1/4.

hence in 4 coins flip two heads in a row is possible.

类似问题

问题 1. 你需要掷硬币多少次才能连续得到两条反面？

解决方案：

Probability of an event = (Number of ways it can occur) / (total number of outcomes),

P(B) = (Number of ways B can happen) / (Total number of outcomes),

Probability of getting a tails = 1/2.

Tossing a coin is an independent event, it is not dependent on how many times it’s been tossed.

Probability of getting 2 tails in a row = probability of getting tails first time×probability of getting tail second time.

Probability of getting 2 tails in a row  = (1/2) × (1/2).

hence in 4 coins flip two tails in a row is possible.

问题 2. 你需要掷硬币多少次才能连续获得三个反面？

解决方案：

Probability of an event = (Number of ways it can occur) / (total number of outcomes),

P(B) = (Number of ways B can happen) / (Total number of outcomes),

Probability of getting a tails = 1/2.

Tossing a coin is an independent event, it is not dependent on how many times it’s been tossed.

Probability of getting 3 tails in a row = probability of getting tail first time×probability of getting tail second time×probability of getting tail third time.

Probability of getting 3 tails in a row  = (1/2) × (1/2) × (1/2).

Hence in 8 coin flip 3 tails in a row is possible.