| Exam Board | AQA |
|---|---|
| Module | Paper 3 (Paper 3) |
| Year | 2018 |
| Session | June |
| Marks | 1 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Discrete Probability Distributions |
| Type | Probabilities in table form with k |
| Difficulty | Easy -1.8 This is a trivial probability distribution question requiring only the basic principle that probabilities sum to 1. Students simply add k + 2k + 4k + 2k + k = 10k = 1, giving k = 1/10. It's a single-step calculation with multiple choice answers provided, making it significantly easier than average A-level questions. |
| Spec | 2.04a Discrete probability distributions |
| \(x\) | 1 | 2 | 3 | 4 | 5 |
| P(\(X = x\)) | \(k\) | \(2k\) | \(4k\) | \(2k\) | \(k\) |
| Answer | Marks | Guidance |
|---|---|---|
| 11 | Circles correct answer | AO1.1b |
| Total | 1 | 1 |
| Answer | Marks | Guidance |
|---|---|---|
| Q | Marking Instructions | AO |
Question 11:
11 | Circles correct answer | AO1.1b | B1
Total | 1 | 1
10
Q | Marking Instructions | AO | Marks | Typical SolutionThe table below shows the probability distribution for a discrete random variable $X$.
\begin{tabular}{|c|c|c|c|c|c|}
\hline
$x$ & 1 & 2 & 3 & 4 & 5 \\
\hline
P($X = x$) & $k$ & $2k$ & $4k$ & $2k$ & $k$ \\
\hline
\end{tabular}
Find the value of $k$.
Circle your answer.
[1 mark]
$\frac{1}{2}$ \quad $\frac{1}{4}$ \quad $\frac{1}{10}$ \quad $1$
\hfill \mbox{\textit{AQA Paper 3 2018 Q11 [1]}}