| Exam Board | WJEC |
|---|---|
| Module | Unit 4 (Unit 4) |
| Year | 2024 |
| Session | June |
| Marks | 3 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Probability Definitions |
| Type | Two-way table probabilities |
| Difficulty | Moderate -0.8 This is a straightforward conditional probability question using a two-way table. Students must identify the conditional sample space (pupils in school or college), then calculate P(both girls | first in school or college) using basic probability rules. The table is clearly presented and the calculation requires only 2-3 steps with no conceptual difficulty beyond understanding conditional probability notation. |
| Spec | 2.03c Conditional probability: using diagrams/tables |
| \cline { 2 - 6 } \multicolumn{1}{c|}{} | School | College | Employment | Other | Total |
| Boys | 33 | 49 | 8 | 2 | \(\mathbf { 9 2 }\) |
| Girls | 40 | 40 | 7 | 1 | \(\mathbf { 8 8 }\) |
| Total | \(\mathbf { 7 3 }\) | \(\mathbf { 8 9 }\) | \(\mathbf { 1 5 }\) | \(\mathbf { 3 }\) | \(\mathbf { 1 8 0 }\) |
\begin{enumerate}
\item The table below shows the destination from school of 180 year 11 pupils. Most pupils either continued education, in school or college, or went into some form of employment.
\end{enumerate}
\begin{center}
\begin{tabular}{ | c | c | c | c | c | c | }
\cline { 2 - 6 }
\multicolumn{1}{c|}{} & School & College & Employment & Other & Total \\
\hline
Boys & 33 & 49 & 8 & 2 & $\mathbf { 9 2 }$ \\
\hline
Girls & 40 & 40 & 7 & 1 & $\mathbf { 8 8 }$ \\
\hline
Total & $\mathbf { 7 3 }$ & $\mathbf { 8 9 }$ & $\mathbf { 1 5 }$ & $\mathbf { 3 }$ & $\mathbf { 1 8 0 }$ \\
\hline
\end{tabular}
\end{center}
A reporter selects two pupils at random to interview. Given that the first pupil is in school or college, find the probability that both pupils are girls.\\
\hfill \mbox{\textit{WJEC Unit 4 2024 Q1 [3]}}