| Exam Board | Edexcel |
|---|---|
| Module | S4 (Statistics 4) |
| Marks | 6 |
| Paper | Download PDF ↗ |
| Topic | F-test and chi-squared for variance |
| Type | F-test two variances hypothesis |
| Difficulty | Moderate -0.8 This question requires only direct table lookups for chi-squared and F-distributions with no calculations or conceptual understanding beyond identifying the correct table entries. Both parts are routine recall exercises typical of S4, requiring students to read statistical tables accurately but involving no problem-solving, interpretation, or multi-step reasoning. |
| Spec | 5.04a Linear combinations: E(aX+bY), Var(aX+bY) |
The random variable $X$ has a $\chi^2$-distribution with 9 degrees of freedom.
\begin{enumerate}[label=(\alph*)]
\item Find P(2.088 < $X$ < 19.023). [3]
\end{enumerate}
The random variable $Y$ follows an $F$-distribution with 12 and 5 degrees of freedom.
\begin{enumerate}[label=(\alph*)]
\item[(b)] Find the upper and lower 5\% critical values for $Y$. [3]
\end{enumerate}
(Total 6 marks)
\hfill \mbox{\textit{Edexcel S4 Q1 [6]}}