跟讀練習: Grade 11: Conditional Probability - 通過影片學習英語口語
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probability is just about figuring out how likely something is to happen if you flip a coin there are
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two possible outcomes heads or tails each one has a one out of two chance so the probability of getting
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heads is one divided by two if you roll a dice and want a three you have one chance out
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of six so probability is always a number between zero and one where zero means impossible and
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one means it's guaranteed to happen this is a simple probability now comes the fun part called
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conditional probability imagine you have a bag with five red balls and five blue balls you close your eyes and
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pick one ball and it turns out to be red what was the probability of finding this red ball yes it's simple
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answer is five out of ten or one half because we have five red balls and five blue balls which means a total of ten balls now without putting it back you pick another ball
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what's the probability this next ball is also red it's no longer five out of ten because one red ball is already gone.
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Now there are four red balls and five blue balls left, which means nine balls in total.
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So your second pick depends on the first.
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This is a conditional probability where what happens next depends on what already happened.
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So in short, conditional probability is just regular probability.
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But you already know something, and you use that knowledge to update your chances.
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Awesome!
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So now that we understand what conditional probability means, let's explore the formula behind it.
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Picture a Venn diagram.
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Imagine two overlapping circles, one for event A, which tells that even A has occurred, and one for event B, which tells that even B has occurred.
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The overlapping area, or this region, represents the cases where both A and B happen together, and we call it as event A intersection with event B.
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Suppose you want find the chance of some event A happening, but you already know that another event B has happened.
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This means we are focusing only on the B circle, and inside that circle the overlapping area is the part that also has A.
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So the probability of A given B is just asking, out of everything in the B circle, how much is also in A?
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That's exactly what conditional probability means.
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Therefore, the formula will now be simple.
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The conditional probability of A given B, which we represent like this, is equal to the probability of both A and B happening together, divided by the probability of just B happening, and that's it.
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Now let's look at a super simple example.
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Imagine there are 100 students in a school.
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Out of them, 50 students play football.
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and out of those 50, 30 also play basketball.
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So, we know that 30 students play both football and basketball.
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Now, suppose someone says, Hey, I picked a student and I already know that the student plays football.
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So, what are the chances that the same student also plays basketball?
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Since we already know this student plays football, we're no longer thinking about all 100 students, and we're only focused on the 50 who play football.
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And out of those 50, 30 also play basketball.
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So the chance that this student plays basketball, given that they play football, is simply 30 divided by 50, which is 3 divided by 5, or 60%.
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So the answer is 60%.
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That's a clear example of conditional probability, where we use what we already know to figure out the chance of something else.
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Now let's look at how this fits into the actual formula.
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Let's call the event of playing basketball as event A and the event of playing football as event B.
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So the probability of both events A and B happening together, that is, a student who plays both basketball and football or P of A intersection B is 30 out of 100.
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That's the overlapping part in the Venn diagram.
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Now the probability of just event B, that is a student playing football, is 50 out of 100.
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So the conditional probability of A given B is simply the probability of both A and B divided by the probability of B.
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That's 30 divided 100 whole divided by 50 over 100, which gives us the same 3 out of 5 or 60 percent.
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This is how the formula works behind the scenes.
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If you enjoy my videos and want to support my channel, consider becoming a Patreon, as it helps me create more awesome content for you.
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Link is in the description.
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Also, you can support my channel by joining our community and becoming a member.
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So good!
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Thank you.
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推薦影片
為什麼要通過這個影片練習口語?
在學習英語的過程中,口語交流是一項至關重要的技能。通過觀看這個有關條件機率的影片,您不僅能理解複雜的數學概念,還能提高您的英語口語能力。影片中的逐步講解使得每一個概念都變得生動有趣,並且可以幫助學習者在實際情境中運用相關表達。這種口語練習不僅適合日常對話,也非常適合進行雅思口語練習,提升您的表達自信心。
語法與句型分析
- 條件機率:影片中提到“如果發生事件 A,那事件 B 的機率是…”這種句型,強調了條件關係。這種表達方式在說英語時非常重要,尤其是當您想解釋一個結果是如何依賴於先前情況時。
- 總數與子集:例如,“在這 100 名學生中,有 50 名學生踢足球”,使用這種結構可以清晰地展示某一總體情況以及其子集,有助於提高您描述資料的能力。
- 分母與分子:用於解釋條件機率公式時,提及“分子是兩個事件同時發生的機率,分母是單一事件發生的機率”,這種邏輯性強的表達,能夠幫助學生更好地理解相關概念。
常見發音陷阱
在影片中,有幾個詞彙可能會給英語學習者帶來發音上的困擾。例如,“probability”和“conditional”這兩個詞的發音較為複雜,尤其是重音和音節劃分。此外,注意句子中的連讀現象,學習如何自然地連線詞語將有助於提高您在實際交流中的流利度。通過模仿與
shadow speech,您可以有效地提高英語發音,掌握更地道的表達方式。
影片中的語法
說話人最常用的結構,並附上影片中的原話:
| 結構 | 影片中的用法 |
|---|---|
| 定語從句 who / which + 從句 — 補充說明人或事物 | balls which means · left, which means · student who plays |
| 現在完成時 have/has + 過去分詞 — 過去發生但與現在仍有關聯的事 | has occurred · has happened |
什麼是跟讀法?
跟讀法 (Shadowing) 是一種有科學依據的語言學習技巧,最初開發用於專業口譯員的培訓,並由多語言者Alexander Arguelles博士普及。這個方法簡單而強大:您在聽英語母語原聲的同時立即大聲重複——就像是一個延遲1-2秒緊跟說話者的影子。與被動聽力或語法練習不同,跟讀法強迫您的大腦和口腔肌肉同時處理並模模擬實的講話模式。研究表明它能顯著提高發音準確性,語調,節奏,連讀,聽力理解和口語流利度——使其成為雅思口語備考和真實英語交流最有效的方法之一。













