| Exam Board | Edexcel |
|---|---|
| Module | S2 (Statistics 2) |
| Marks | 7 |
| Paper | Download PDF ↗ |
| Topic | Discrete Probability Distributions |
| Type | Direct probability from given distribution |
| Difficulty | Moderate -0.8 This is a straightforward S2 question testing basic probability calculations for three standard distributions (binomial, Poisson, normal). Each part requires only direct application of formulas or tables with no problem-solving, conceptual insight, or multi-step reasoning—purely routine recall and calculation, making it easier than average but not trivial since it requires familiarity with statistical tables and standardization. |
| Spec | 2.04c Calculate binomial probabilities2.04f Find normal probabilities: Z transformation5.02k Calculate Poisson probabilities |
The random variable R has the binomial distribution B(12, 0.35).
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\item Find P(R ≥ 4). [2]
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The random variable S has the Poisson distribution with mean 2.71.
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\item Find P(S ≤ 1). [3]
\end{enumerate}
The random variable T has the normal distribution N(2.5, 5²).
\begin{enumerate}[label=(\alph*)]
\setcounter{enumi}{2}
\item Find P(T ≤ 18). [2]
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\hfill \mbox{\textit{Edexcel S2 Q2 [7]}}