| Exam Board | Edexcel |
|---|---|
| Module | S1 (Statistics 1) |
| Marks | 5 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Conditional Probability |
| Type | Incomplete two-way table completion |
| Difficulty | Easy -1.3 This is a straightforward S1 question requiring basic arithmetic to complete a two-way table (simple subtraction) followed by reading probabilities directly from the table. Part (c) involves conditional probability but only requires dividing two numbers from the completed table. No conceptual challenge or problem-solving insight needed. |
| Spec | 2.03b Probability diagrams: tree, Venn, sample space2.03d Calculate conditional probability: from first principles |
| \cline { 2 - 4 } \multicolumn{1}{c|}{} | Studio | Live | Total |
| Jazz | 13 | 16 | |
| Blues | |||
| Total | 8 | 30 |
| Answer | Marks | Guidance |
|---|---|---|
| (a) Completed table with Studio: 13, Live: 3, Total: 16 for Jazz; Studio: 9, Live: 5, Total: 14 for Blues; Studio: 22, Live: 8, Total: 30 for Total | A2 | |
| (b) \(\frac{5}{30} = \frac{1}{6}\) | A1 | |
| (c) \(\frac{13}{22}\) | M1 A1 | Total 5 marks |
**(a)** Completed table with Studio: 13, Live: 3, Total: 16 for Jazz; Studio: 9, Live: 5, Total: 14 for Blues; Studio: 22, Live: 8, Total: 30 for Total | A2 |
**(b)** $\frac{5}{30} = \frac{1}{6}$ | A1 |
**(c)** $\frac{13}{22}$ | M1 A1 | Total 5 marks
---\begin{enumerate}
\item Joel buys a box of second-hand Jazz and Blues CDs at a car boot sale.
\end{enumerate}
In the box there are 30 CDs, 8 of which were recorded live. 16 of the CDs are predominantly Jazz and 13 of these were recorded in the studio. This information is shown in the following table.
\begin{center}
\begin{tabular}{ | c | c | c | c | }
\cline { 2 - 4 }
\multicolumn{1}{c|}{} & Studio & Live & Total \\
\hline
Jazz & 13 & & 16 \\
\hline
Blues & & & \\
\hline
Total & & 8 & 30 \\
\hline
\end{tabular}
\end{center}
(a) Copy and complete the table above.
Joel picks a CD at random to play first.\\
Find the probability that it is\\
(b) a Blues CD that was recorded live,\\
(c) a Jazz CD, given that it was recorded in the studio.\\
\hfill \mbox{\textit{Edexcel S1 Q1 [5]}}