| Exam Board | Pre-U |
|---|---|
| Module | Pre-U 9794/3 (Pre-U Mathematics Paper 3) |
| Year | 2020 |
| Session | Specimen |
| Marks | 6 |
| Topic | Normal Distribution |
| Type | Multiple probability calculations only |
| Difficulty | Easy -1.2 This is a straightforward application of normal distribution with standardization to z-scores and table lookup. Both parts require only the routine procedure of calculating z = (x - μ)/σ and reading from tables, with no problem-solving or conceptual challenges beyond basic recall of the normal distribution method. |
| Spec | 2.04e Normal distribution: as model N(mu, sigma^2)2.04f Find normal probabilities: Z transformation |
The times for a motorist to travel from home to work are normally distributed with a mean of 24 minutes and a standard deviation of 4 minutes. Find the probability that a particular trip from home to work takes
\begin{enumerate}[label=(\alph*)]
\item more than 27 minutes, [3]
\item between 20 and 25 minutes. [3]
\end{enumerate}
\hfill \mbox{\textit{Pre-U Pre-U 9794/3 2020 Q1 [6]}}