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2.3.3 Conditional probability (A-level only)

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Question 97

In a scientific research facility with 200 doctoral candidates, researchers are categorized by their primary field: Biology, Chemistry, or Physics. The following table summarizes the distribution of researchers and whether they have been awarded a research Grant or Not.

\begin{center} \begin{tabular}{|l|c|c|} \hline & Grant awarded (G) & No Grant (G')\\ \hline Biology (B) & 24 & 36 \\ \hline Chemistry (C) & 42 & 28 \\ \hline Physics (P) & 30 & 40 \\ \hline \end{tabular} \end{center}

A researcher is selected at random from the facility. Determine:

a.

P(C)P(C)P(C)

[1]
b.

P((B∩G)′)P((B \cap G)')P((B∩G)′)

[2]
c.

P(G∣P)P(G | P)P(G∣P)

[2]
d.

Let A A\,A be the event that a researcher has published a first-author article this year. Given that 30% of Biologists have published a first-author article, 10% of Chemists have published a first-author article, and 20% of Physicists have published a first-author article,

describe the structure of a Venn diagram to represent the events BBB, CCC, P P\,P and AAA.

[1]
e.

find the probability that a randomly selected researcher has published a first-author article this year.

[2]

2.3.3 Conditional probability (A-level only) Questions

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