| Exam Board | OCR |
|---|---|
| Module | AS Pure (AS Pure Mathematics) |
| Year | 2017 |
| Session | Specimen |
| Marks | 3 |
| Topic | Measures of Location and Spread |
| Type | Using random number tables/generators |
| Difficulty | Easy -1.8 This question tests basic understanding of sampling bias and simple application of random number tables. Part (a) requires only a straightforward explanation of convenience sampling bias. Part (b) is purely mechanical: identify which numbers fall in range 1-253, skip duplicates and out-of-range values. No calculation or problem-solving required—just pattern recognition and basic logic. |
| Spec | 2.01c Sampling techniques: simple random, opportunity, etc2.01d Select/critique sampling: in context |
8 A club secretary wishes to survey a sample of members of his club. He uses all members present at a particular meeting as his sample.
\begin{enumerate}[label=(\alph*)]
\item Explain why this sample is likely to be biased.
Later the secretary decides to choose a random sample of members.\\
The club has 253 members and the secretary numbers the members from 1 to 253 . He then generates random 3-digit numbers on his calculator. The first six random numbers generated are 156, 965, 248, 156, 073 and 181. The secretary uses each number, where possible, as the number of a member in the sample.
\item Find possible numbers for the first four members in the sample.
\end{enumerate}
\hfill \mbox{\textit{OCR AS Pure 2017 Q8 [3]}}