| Exam Board | Edexcel |
|---|---|
| Module | S1 (Statistics 1) |
| Paper | Download PDF ↗ |
| Topic | Conditional Probability |
| Type | Basic two-way table probability |
| Difficulty | Easy -1.2 This is a straightforward S1 question testing basic probability concepts: reading from a two-way table, calculating simple probabilities, conditional probability with given information, constructing a standard tree diagram, and applying Bayes' theorem. All parts follow standard textbook procedures with no problem-solving insight required—purely mechanical application of formulas to clearly presented data. |
| Spec | 2.03a Mutually exclusive and independent events2.03b Probability diagrams: tree, Venn, sample space2.03c Conditional probability: using diagrams/tables2.03d Calculate conditional probability: from first principles |
| Live close |
| |||
| Management | 6 | 14 | ||
| Administration | 25 | 10 | ||
| Production | 45 | 25 |
4. The employees of a company are classified as management, administration or production. The following table shows the number employed in each category and whether or not they live close to the company or some distance away.
\begin{center}
\begin{tabular}{ | l | c | c | }
\hline
& Live close & \begin{tabular}{ c }
Live some \\
distance away \\
\end{tabular} \\
\hline
Management & 6 & 14 \\
\hline
Administration & 25 & 10 \\
\hline
Production & 45 & 25 \\
\hline
\end{tabular}
\end{center}
An employee is chosen at random.\\
Find the probability that this employee
\begin{enumerate}[label=(\alph*)]
\item is an administrator,
\item lives close to the company, given that the employee is a manager.
Of the managers, $90 \%$ are married, as are $60 \%$ of the administrators and $80 \%$ of the production employees.
\item Construct a tree diagram containing all the probabilities.
\item Find the probability that an employee chosen at random is married. (3 marks)
An employee is selected at random and found to be married.
\item Find the probability that this employee is in production.
\end{enumerate}
\hfill \mbox{\textit{Edexcel S1 Q4}}