Probability

兩次擲骰子 - 順序相同

  • April 17, 2017

我目前正在 Coursera 上學習統計推理課程。在其中一項作業中,出現了以下問題。

| Suppose you rolled the fair die twice. 
   What is the probability of rolling the same number two times in a row?

1: 2/6
2: 1/36
3: 0
4: 1/6

Selection: 2

| You're close...I can feel it! Try it again.

| Since we don't care what the outcome of the first roll is, its probability is 1. 
   The second roll of the dice has to match the outcome of the first, 
   so that has a probability  of 1/6. The probability of both events occurring is 1 * 1/6.

我不明白這一點。我知道這兩個骰子是獨立的事件,它們的概率可以相乘,所以結果應該是 1/36。

你能解釋一下,為什麼我錯了嗎?

連續兩次滾動特定數字的概率確實是 1/36,因為兩次滾動中的每一次都有 1/6 的機會獲得該數字(1/6 x 1/6)。

連續滾動任何數字兩次的概率是 1/6,因為有六種方法可以連續滾動特定數字兩次 (6 x 1/36)。另一種思考方式是你不關心第一個數字是什麼,你只需要第二個數字來匹配它(概率為 1/6 )。

引用自:https://stats.stackexchange.com/questions/274135

comments powered by Disqus